Abstracts NEVADA 80 Laramie Cheyenne WYOMING Wendover 76 Salt Lake City UTAH COLORADO New Mexico Symposium 25

The Twenty-First Annual New Mexico 6 Denver 6 Mineral Symposium was held November 11 Ely 70 and 12, 2000, at New Mexico Institute of 50 6 Grand Junction Mining and Technology, Socorro. Following 70 550 Colorado Springs are abstracts from all talks given at the sym- 24 Pueblo posium. 191 15 2 93 666 PSEUDOMORPH CITY—THE MINERALOG- 160 ICAL TREASURES OF THE GRAPHIC– Alamosa WALDO AND KELLY MINES, MAGDA- Durango 285 OK LENA DISTRICT, NEW MEXICO, Robert 5 64 87 ARIZONA NEW MEXICO 666 Eveleth and Virgil W. Lueth, New Mexico 84 Springer Bureau of Mines and Mineral Resources, New 54 Mexico Institute of Mining and Technology, 191 Socorro, NM 87801 Santa Fe Gallup (Location 1 on index map) TEXAS 40 Flagstaff 40 Any discussion of the Magdalena mining district Kingman 7 in Socorro County, New Mexico, ultimately 666 Albuquerque 6 focuses on the beautiful blue-green gem variety 180 Clovis CA 60 of the mineral and for good reason. 17 54 Specimens from the Kelly mine have become 60 Socorro famous the world over for their superb color and 1 Phoenix 380 luster. The Kelly mine, as a result, has tended to 10 Globe 666 Roswell enjoy all of the mineralogical accolades over the 180 70 25 past 50 yrs or so, and our very own mineralogi- 70 Alamogordo City cal museum here in Socorro is responsible, at 8 Hobbs 4 least in part. Las 3 Cruces A reason for the fame of the Kelly is the C. T. Tucson 10 Carlsbad Brown collection. Acquired by the New Mexico Deming 19 180 School of Mines in 1938, the collection contains 20 El Paso an abundance of superb , most of TEXAS which have been on open display to the public 285 Gulf SONORA CHIHUAHUA 10 since that time. of 10 However, with the mineral museum’s acquisi- California Van Horn tion of the Mahlon T. Everhart collection in 1990, it became apparent that there is another mine in blatonite. A second new uranium mineral from The basal siltstone is the host for most of the the district that has produced an equally impres- the mine has recently been submitted to the mine's . They are found as microscopic sive array of mineralogical treasures. That mine International Mineralogical Association for crystals locally concentrated in two different is the Graphic–Waldo, located over the hill to the approval. The Jomac mine is the world's second assemblages, a copper sulfate assemblage and a north of the Kelly. C. T. Brown’s mining partner reported location for the minerals swamboite blatonite assemblage. Minerals found in the cop- in the district was Asa B. Fitch, and he, like and mbobomkulite. The mine saw most of its ore per sulfate assemblage include anhydrite, car- Brown, assembled an impressive collection of production in the 1950s and had an active claim bonate-cyanotrichite, antlerite, malachite, azu- minerals. Whereas Brown tended to focus his until 1985. Obviously, the mine was a wonderful rite, serpierite, alunite, sparse smithsonite, bolt- attentions on the Kelly, Fitch collected primarily source for interesting minerals. Unfortunately, woodite, and very rare brochantite. The blatonite at the Graphic. Thus, the two collections comple- the mine lies within the boundaries of the Glen assemblage can have sparse amounts of the min- ment one another. Mahlon acquired the Fitch col- Canyon National Recreation Area, and it was erals found in the copper sulfate assemblage, but lection during the 1930s and subsequently reclaimed in 1992. Mineral collecting since then has a greater amount of carbonate mineraliza- donated it to the museum in 1990. has not been allowed. tion. This latter assemblage has blatonite; ura- Specimens in the Fitch/Everhart collection are The Jomac mine's three adits lie in the nopilite; increased amounts of malachite and remarkable in that they clearly demonstrate that Shinarump Conglomerate Member of the smithsonite; sparse amounts of swamboite, zinc carbonate has tended to replace many of the Triassic Chinle Formation. Petrified wood, coal, sklodowskite, rutherfordine, schoepite, meta- other ore minerals in the Graphic orebody— and sooty black organic debris are scattered schoepite, meta-autunite, and mbobomkulite; sometimes with spectacular results. Examples of throughout the conglomerate. The organic the recently submitted uranium mineral; an such replacements are seen as smithsonite remains, apparently setting up a reducing envi- unidentified orange uranium mineral; and some pseudomorphs of barite, calcite, cerussite, ronment, make the sediments more amenable for fine-grained, yellow uranium minerals. Impur- cuprite, galena, and native copper. With this pre- the precipitation of primary minerals. Uraninite ities in the minerals cause various changes in sentation, the authors hope to place the and the sulfide minerals pyrite, chalcopyrite, their habits, making identifications challenging. Graphic–Waldo back where it belongs—on an and sphalerite were deposited. Tiny specks of Cobalt and nickel are common in trace amounts equal mineralogical standing with the Kelly. cuprite are very common in a basal siltstone, but in most of the secondary copper minerals. cuprite may or may not be a primary mineral. The Jomac mine's portals were sealed with MINERALOGY OF THE JOMAC MINE, SAN Oxidation of these minerals led to the formation mortar and backfilled, and the access road has JUAN COUNTY, UTAH, Patrick E. Haynes, of an unusual assortment of mostly copper and been blocked with boulders. Despite the recla- P.O. Box 1531, Cortez, CO 81321 uranium minerals. The minerals hematite, mation efforts, previously recovered specimens (Location 2 on index map) jarosite, hydronium jarosite, and limonite are are producing interesting results. Two of the The Jomac mine is located on Brown’s Rim, in common. Also common in the conglomerate are remaining unidentified uranium minerals have the White Canyon mining district of San Juan coconinoite and metazeunerite. A mixture of unique X-ray diffraction (XRD) patterns. County, Utah. It has recently become the type asbolan–birnessite occurs as dendritic smears on locality for a uranium-carbonate mineral named surfaces. TAKING CARE OF THE LITTLE THINGS:

February 2001 NEW MEXICO GEOLOGY 21 THE MICROMOUNT COLLECTIONS AT (Location 4 on index map) studying the crystal fill and textures in THE ARIZONA–SONORA DESERT MUSE- One of the geologically interesting features of spherulites and geodes, we hope to piece togeth- UM, Anna M. Domitrovic, Collections Manager, Rockhound State Park, in southern New Mexico, er the different processes through time that Mineralogist, Arizona–Sonora Desert Muse- is the presence of many spherulites within the formed them. The banding found within some um, 2021 N. Kinney Road, Tucson, AZ 85743 rhyolite lava. The spherulites range in size from spherulites and geodes consists of multiple lay- (Location 3 on index map) less than 1 mm to greater than 30 cm, and many ers of different colored agate, chalcedony, and The Arizona–Sonora Desert Museum’s Perma- are solid, concentrically zoned, dark-gray to local quartz and may have been formed by fluids nent Mineral Collection has 14,250 catalogued pinkish colored material with a distinct, nodu- supersaturated in silica (Fournier, 1985). The dif- specimens. Over the course of its 25-yr history, lar, reddish core. Others consist of the same ferent colors of the bands are a result of trace minerals have been purchased, exchanged, and material but are partly hollow. A third popula- amounts of impurities, such as iron (red), man- donated. Acquisitions have come one specimen tion consists of two distinct parts: a dark-gray to ganese (black, pink), cobalt (blue, violet-red), at a time or, especially in the case of the micro- pinkish outer part that appears similar to the copper (green, blue), chromium (orange-red), mounts, thousands in one acquisition. material that forms the solid spherulites and a nickel (green), etc. The micromount collection is extremely impor- white, blue, or gray inner part, or core, which is Faceted quartz crystals indicate that the fluids tant to the Desert Museum. Because many rare or recognizable as agate, chalcedony, and quartz were somewhat supersaturated with silica, and unusual minerals generally occur only as micro- crystals. These two parts appear to be a shell and that precipitation occurred under relatively scopic specks, micromounts provide the means a filling. This type of filled spherulitic form is slow-changing conditions (Fournier, 1985). Tilted of acquiring as many species as possible that commonly called a “thunderegg.” In order to thundereggs, locally found at Rockhound State occur within the boundaries of the Desert gain some insight into the process by which Park, are filled with horizontal layers of agate Museum’s interpretive realm—the Sonoran these spherulites form, samples were examined and chalcedony that are overlain by concentric- Desert region of Arizona and Baja and Sonora, using back-scattered electron imaging and quali- banded agate and chalcedony; the contact Mexico. The micromount collections are valuable tative X-ray analysis and imaging using a between the layered and banded agate resembles research tools. They allow researchers to see rep- Cameca SX-100 electron microprobe. Microprobe an angular unconformity. These thundereggs resentative minerals of a given locality in one sit- examination of the "shell" part of Rockhound record either small local landslides or tilting of ting. They provide mineralogists with a visual spherulites shows that they are composed of local fault blocks within the Little Florida means of identifying other species by physical intergrown crystals of quartz (SiO2), alkali feld- Mountains while the crystals were precipitating comparison when other means of identification spar (K,Na)[AlSi3O8], plagioclase feldspar from the fluid (Shaub, 1979; Colburn, 1999). such as X-ray and scanning electron microscopy Na[AlSi3O8]-Ca[Al2Si2O8], and magnetite (Fe3O4). References are not readily available. These are just two of The images from the microprobe show that the Colburn, R., 1999, The formation of thundereggs the major uses for the micromount collections at spherulites are formed either of intimately inter- (lithophysae): Robert Colburn, CD-ROM, 385 pp. the Desert Museum. grown quartz, feldspar, and magnetite, or of Dunbar, N. W., Jacobs, G. K., and Naney, M. T., Micromounts have been a part of the Desert bands of quartz systematically interspersed with 1995, Crystallization processes in an artificial Museum’s Permanent Mineral Collection since bands of intergrown feldspar and quartz. The magma: Variations in crystal shape, growth rate, the middle 1970s. More than two decades ago, bands range in width from approximately 100 to and composition with melt cooling history: their importance was impressed upon the muse- 200 microns, and it is this banding that produces Contributions to Mineralogy and Petrology, v. um administrators, which resulted in getting the the concentric structure that is apparent in some 120, pp. 412– 425. first of the Desert Museum’s micromount collec- parts of the spherulites. The reddish, nodular Fournier, R. O., 1985, The behavior of silver in tion started. Through the efforts of William core of the spherulites is composed mainly of hydrothermal solutions; in Berger, B. R., and Bethke, P. M. (eds.), Geology and geochemistry of Hunt, Robert Mudra, Earl Pemberton, and intergrown quartz and plagioclase, whereas the epithermal systems: Reviews in Economic Arthur Roe hundreds of micromounts have a outer part of the spherulites contains quartz and Geology, v. 2, pp. 45 – 62. lasting home within the confines of the muse- alkali feldspar. Jacobs, G. K., Dunbar, N. W., Naney, M. T., and um’s mineral vault. Entire micromount collec- The observed patterns in the spherulites sug- Williams, R. T., 1992, In-situ vitrification: tions were generously donated by Edna gest that they may have formed during the cool- Observations of petrological processes in a man- Andregg, Marvin Deshler, Jean Rogers, and ing of the rhyolite lava. Similar spherulitic forms, made magmatic system: EOS, Transactions of the Frances Saunders. The most substantial of these with similar internal growth features, were American Geophysical Union, v. 73, pp. 401– 411. donations was that of Marvin Deshler. The observed in an artificial melt that was rapidly Lofgren, G., 1970, Experimental devitrification rate Desert Museum is proud to own 4,625 micro- cooled (Jacobs et al., 1992; Dunbar et al., 1995). of rhyolitic glass: Geological Society of America, mounts in this valuable collection. The Andregg The temperature of the artificial melt was moni- Bulletin, v. 81, pp. 553 –560. Collection numbers 2,069, the Saunders Col- tored during the cooling process, and exothermic Lofgren, G., 1971, Spherulitic textures in glassy and lection numbers 833, and the Rogers Collection crystallization was observed at high tempera- crystalline rocks: Journal of Geophysical numbers 252. These numbers alone attest to the tures (1,100°C). Spherulitic growth occurred dur- Research, v. 76, no. 23, pp. 5635 – 5648. value of their acquisition to the Desert Museum. ing this crystallization process, and the internal Shaub, B. M., 1979, Genesis of thundereggs, geodes, Most recently, the Desert Museum acquired a structure of the spherulites was indistinguish- and agates of igneous origin: Lapidary Journal, v. collection of 232 regional micromounts from the able from the internal structure of Rockhound 32, pp. 2340–2354, 2548 –2566. collection of the late G. Robert Massey. spherulites. This similarity suggests that the Several Tucson micromounters continue the Rockhound spherulites may have formed by a ARIZONA’S COLORFUL CALCITES, Les Desert Museum’s efforts in adding to its micro- similar high-temperature rather than sub-solidus Presmyk, Salt River Project Fuels Division, P.O. mounts. Museum docent and volunteer Mark process. Furthermore, the feathery and non- Box 52025 , Phoenix, AZ 85072 Goldberg presently handles micromount repairs equant crystal shapes observed in the Arizona certainly contains its share of potential and additions to the Permanent Mineral Rockhound spherulites are very similar to crys- calcite-producing geology. The northern third of Collection. Sven Bailey had the job in the 1980s. tal forms described by Lofgren (1970, 1971) for the state consists of the Colorado Plateau and Carol Amshoff, co-owner of Tucson’s Kino Rocks crystals that grew rapidly at high temperatures contains exposed layers of limestone hundreds & Minerals, and Desert Museum docent Janet (~700°C), probably very soon after the rhyolitic of feet thick. As one moves south, limestone beds Reue demonstrate and instruct in the fine art of lava was erupted onto the Earth's surface. are not only exposed in the mountain ranges and micromounting for museum visitors at the annu- The agate, chalcedony, and quartz veins and valleys, but a few of the layers play host to some al Mineral Madness Showcase & Sale held in open-space fillings within voids in the spher- of the richest copper mines in the world. January every year. Arthur Roe was initially ulites formed later by multiple cycles of hydro- Whereas Arizona is not known for large water- responsible for photographing the first of the thermal fluids. Hydrothermal fluids are a mix- courses of calcite crystals similar to those found museum’s micromounts. That tradition is contin- ture of late-stage fluids escaping the magma and in the Tri-State area, there are a number of local- ued today by Green Valley photographer local ground water. Some of these fluids move ities that have produced distinctive and brightly William Meinert. into hollow spherulites through fractures and colored calcite crystals. The specimen colors precipitate crystals along the walls of the inner range from colorless and white to black and vir- cavity, forming geodes and filled geode-like tually every hue in between. THE ORIGIN OF RHYOLITIC SPHERULITES spherulites. The Rockhound spherulites show The journey starts at Arizona’s newest state AT ROCKHOUND STATE PARK, NEW evidence of multiple hydrothermal events park, the Kartchner Caverns. The caverns were MEXICO, Nelia W. Dunbar and Virginia T. expressed by multiple colors and textures of fills, discovered in the mid-1970s by two avid cave McLemore, New Mexico Bureau of Mines and which could be accounted for by different tem- explorers. They managed to keep their discovery Mineral Resources, New Mexico Institute of peratures and fluid compositions. By carefully Mining and Technology, Socorro, NM 87801 secret for a number of years. When it became

22 NEW MEXICO GEOLOGY February 2001 obvious that the word was beginning to leak out, ated gypsum or pyrite crystals. a small prospect about 100 m east of the main pit. they went to the Kartchner family, who owned Continuing south and to the west is the copper This rock contained unknown crystals of orange the land where the caverns are located and made mine at Ajo. The New Cornelia mine has a long and black acicular minerals in the vesicles. them aware of their discovery. Together, they history and has produced some of the reddest Following the November 1999 New Mexico decided the caverns should be preserved for the cuprite-included calcite crystals in the state. It is Mineral Symposium, both authors traveled to benefit of the State of Arizona, and negotiations best known for its crystallized coppers and azu- Brushy Mountain to investigate the minerals of began with the State Parks Department. After an rite and malachite specimens; however, it is one this prospect. The black acicular mineral extended design and construction period, the of the finest localities for red calcite crystals. appeared, with some certainty, to be pseudo- first part of the caverns was opened to the world Before heading north one last time, the Red brookite, and the quartz (amethystine) was obvi- in 1999. The formations are great, but even more Cloud mine should at least be mentioned. The ous, but identification of several other minerals spectacular is the effort to preserve the interior in major gangue mineral in the vein is brown cal- was in question. Further study and microprobe a pristine condition—with more effort to come. cite. Whereas a number of localities in Arizona analysis by Paul Hlava of Sandia National Next on the journey are the great copper mines contain this dark-brown calcite, the Red Cloud is Laboratory (pers. comm. 1999) have recognized of Bisbee. In the early days of mining at this loca- the only place a collector might want one of these the following species: tion, the miners learned that one of the ways to specimens—particularly if there are wulfenites Pseudobrookite: Black, lustrous blades up to 2 find orebodies was to look for caverns. When the scattered across the calcite. Otherwise, they are mm, some found on amethystine quartz, and sulfide minerals oxidized, the total volume the ugliest calcite crystals I have collected. also as inclusions in the quartz. The crystals decreased, which left a void above the oxide Leaving the Red Cloud, there are three locali- are associated with tridymite, spessartine, and zones. Because the sulfide mineralization was ties left that are noteworthy. The Bruce mine at aegerine. emplaced in limestone beds, open voids were left Bagdad produced colorless to white, highly lus- Aegerine: Slender, prismatic crystals with steep in which calcite and aragonite could form. Some trous crystals that display fishtail twinning up to pyramidal terminations to 1.5 mm. These crys- of the percolating waters moved through copper 3 inches long. Unfortunately, the miners broke tals are orange to burnt-umber color. Aegerine minerals, so not only were white calcite crystals the larger twins off, so it is unusual to have a is also found as short (0.2 mm), brown pris- 1 formed but also a number of pale-blue and green specimen with twins over 1 ⁄2 inches long still on matic crystals that are opaque with a dull lus- formations resulted. Over the years of copper matrix. The same thing occurred in the initial col- ter. They are often found with monazite. mining, a number of watercourses were encoun- lecting at the Brushy Creek mine in Missouri Monazite: Monazite is found as dull-yellow, tered in many of the mines. These produced when the watercourse with the gray calcites and subhedral crystals up to 0.4 mm in length. some very distinctive specimens, including the iridescent marcasite was encountered. They are uncommon but are found with the iron-stained, hexagonal, “poker-chip” style crys- Heading east and down into the Verde Valley, dull-brown aegerine crystals. tals. Of course, the most desirable of the Bisbee a locality known to any rockhound or mineral Hematite: Small brown to black tabular crystals calcites are those colored bright red and bright collector in Arizona is the Salt mine. It was the about 0.2 mm across are sparsely found. green by included cuprite and malachite, respec- second locality I ever went to, and I still direct Associated with the short, brown aegerine and tively. people to the area to collect. It is known for its monazite crystals. In spite of a lot of mining activity in the eastern calcite after glauberite pseudomorphs, along Tridymite: Aggregates of bladed, twinned, fourth of the state, there is a dearth of good cal- with gypsum after glauberite, aragonite after bluish-gray, transparent crystals with a vitre- cite localities. One has to travel back to the cen- glauberite, and just plain glauberite crystals. ous luster are commonly found in the litho- tral part of the state to the copper mines of The last locality of our journey is in Mohave physae. Individual crystals are about 0.5 mm Globe–Miami, Superior, Ray, and San Manuel to County in western Arizona. A vein of calcite across. find collectible calcites. The Old Dominion mine crystals was discovered that is more typical of Quartz: Much of the quartz at Brushy Mountain in Globe produced white calcites, and though English crystallization than any other Arizona is amethystine and gemmy with a vitreous lus- not colorful, the contrasting matrix makes for locality. The locality produced specimens from ter. Pseudobrookite is often found on and as pleasing specimens. The calcite crystals occur on the size of thumbnails to the size of a large cabi- inclusions in the quartz. chrysocolla-stained drusy quartz pockets and on net, with crystals in excess of an inch. The col- Spessartine: Spessartine crystals are uniformly just plain chrysocolla. There are cuprite included lecting ended when the area changed ownership small (0.5 mm), black trapezohedrons. They calcites that come from here as well. and the vein got too deep. are found with pseudobrookite, aegerine, The Magma mine at Superior produced small tridymite, and quartz (amethyst). pockets of calcites throughout its history. It is Opal: Colorless, hyaline opal commonly coats much more famous for its barites and pyrites, so A NEW PSEUDOBROOKITE LOCATION IN the minerals at Brushy Mountain. It fluoresces the calcites have been somewhat overlooked. TAOS COUNTY, NEW MEXICO, Ramon S. green under short wave UV. The calcites range from pink manganocalcites DeMark, 530 E. Arch Street, Marquette, MI Brushy Mountain is the first documented loca- (collected at the bottom of number 5 shaft in 150° 49855, and Jessie M. Kline, 5094 NDCBU, 511 tion for pseudobrookite in Taos County and water) to a number of white and off-white speci- Apache, Taos, NM 87571 northern New Mexico. It also appears to be the mens of various crystal shapes. The best single (Location 5 on index map) first reported occurrence of aegerine and pocket of calcites ever collected at the Magma The No Agua mining district in northern Taos tridymite in Taos County. Finding pseudo- mine was discovered in one of the drift headings County, New Mexico, is composed of several brookite and other minerals at Brushy Mountain in the fall of 1986. A pocket approximately 5 ft mines that have been operated for perlite and suggests that investigation of other rhyolites in long by 1 ft wide by 4 ft high was discovered that scoria since the 1950s. The mining district is the TPVF might result in additional discoveries. contained clear, twinned crystals up to 3 inches located within the Taos Plateau volcanic field Reference across sitting on a dark crystallized matrix. (TPVF), which consists of mostly Tertiary vol- Lipman, P. W., and Mehnert, H. H., 1979, The Taos The copper mine at Ray (now called Kearny canics 2–5 m.y. old. The most voluminous and Plateau volcanic field, northern Rio Grande rift, because the town of Ray has long since become widespread rock type of the TPVF is the 3.6–4.5 New Mexico; in Riecker, R. E. (ed.), Rio Grande part of the open pit) has produced a number of m.y.-old Servilleta basalt (Lipman and Mehnert, rift—tectonics and magmatism: American Geo- nice calcite specimens over the years. The best 1979). physical Union, Washington, D.C., pp. 289– 311. pocket consisted of yellow calcite crystals with In the fall of 1998, a field trip guided by Dr. cuprite inclusions. Within the past 2 yrs, a large Tony Benson of the University of New Mexico at AN UPDATE ON THE FLUORESCENT MIN- quantity of chrysocolla was mined, which Taos was conducted to look at various rocks and ERALS OF NEW MEXICO, Dru E. Wilbur and included vugs with white calcite crystals. structures of the TPVF. One of the stops was at Virgil W. Lueth, New Mexico Bureau of Mines Although these aren’t colorful calcites per se, it is the open pit of the former United Perlite and Mineral Resources, New Mexico Institute a truly colorful association. Corporation mine on Brushy Mountain, which is of Mining and Technology, Socorro, NM 87801 San Manuel is a large, underground copper about 12.5 mi east-northeast of Tres Piedras and Twenty-three mineral species, previously unre- mine about 50 mi north of Tucson. Unlike some 3.5 mi west of the Rio Grande. Brushy Mountain, ported from New Mexico as fluorescent, have of the other great copper deposits that were a local lava dome of silicic rhyolite containing been identified in recent work at the Mineral deposited in limestone beds, this orebody is a phenocrysts of quartz and sodic sanidine, is Museum of the New Mexico Bureau of Mines porphyry. There are a number of small cracks overlain by lava flows of olivine-augite andesite and Mineral Resources (see accompanying and openings in the rock mass that have allowed and hornblende rhyodacite. The rhyolite has table). Three of these, allophane, chabazite, and calcite crystals to grow. While not on a caliber yielded a K–Ar age of 22.3 m.y. (Lipman and rhodochrosite, have responses that are highly with the Magma mine or the Ray mine, they are Mehnert, 1979). esthetic and deserve to have a place in any col- interesting nonetheless. Some occur with associ- During the visit, one of the authors, Jessie M. Kline, picked up some lithophysal rhyolite from lector’s display. The total number of described

February 2001 NEW MEXICO GEOLOGY 23 fluorescent mineral species now known from New record of minerals from New Mexico displaying a fluorescent response. New Mexico is up to 62. Mineral SW response LW response This presentation is a product of an ongoing species Chemical formula (257 nm) (365 nm) Locality project to update the New Mexico Bureau of allophane Al2O3,SiO2,H2O dark-blue bright-blue Juanita mine, Magda- Mines and Mineral Resources’ (NMBMMR) green green lena district, Socorro Circular 15 (Tables of fluorescent and radioactive County minerals). Since 1947, the NMBMMR has contin- anhydrite CaSO4 creamy creamy Carlsbad, Eddy County uously published tables of fluorescent minerals. yellow yellow These have been exhaustive lists that encom- bertrandite Be4Si2O7(OH)2 yellow none Harding pegmatite, passed all known species of fluorescent as well Taos County as radioactive minerals. There have been three chabazite (Ca,K,Na)4Al4Si8O24-12H2O violet violet East Fork, Gila River, editions of Circular 15 that have periodically Grant County reviewed and revised these lists (Hersley, 1947; clinohumite (Mg,Fe)9(SiO4)4(F,OH)2 peach to yellow to West of Camel Mtn., grayish-white white Luna County Sun, 1955; Stephenson, 1962). The current revi- dickite Al2Si2O5(OH)4 violet violet Mex-Tex mine, Han- sion, to be issued as a bulletin, will focus entire- sonburg district, ly on the fluorescent minerals of New Mexico. Socorro County New to the report will be locality and collecting fluorapophyllite KCa4Si8O20(F,OH)-8H2O violet light-violet Gila Mountains, Grant information, fluorescent responses, and illustra- County tions of specimens in both plain and ultraviolet gonnardite (Na,Ca)6-8[(Al,Si)20O40]-12H2O violet violet Pinos Altos, Grant light. In addition to Circular 15, the other prima- County ry source for New Mexico fluorescent mineral helvite Mn4Be3(SiO4)3S yellow to pale-yellow Victorio district, information has been a 1987 New Mexico pale-white Luna County Geological Society (NMGS) article by Peter heulandite (Ca,Na,K)9[Al9Si27O72]~24H2O pale-white pale-white Gila Mountains, Grant Modreski that includes a good treatment of the County science of the fluorescent phenomena. Since the levyne (Ca0.5,Na,K)6[Al6Si12O36]~17H2O violet violet West Fork, Gila River, time of the publication of these reports, the study Grant County and enjoyment of mineral fluorescence has mesolite Na16Ca16[Al48Si72O240]-64H2O white white Middle Fork, Gila grown from a very specialized interest into one River, Grant County of wider appeal. The appearance of inexpensive minium Pb2PbO4 very dark dull-orange Hillsboro district, and easily obtainable fluorescent lamps has orange Sierra County allowed a great number of people to enjoy this mordenite (Na2,Ca,K2)4[Al8Si40O96)-28H2O violet violet Santa Rita district, Grant County phenomenon. It is hoped that this publication will help to increase awareness of the mineral phlogopite KMg3AlSi3O10(OH)2 none yellow on Picuris district, crystal edges Taos County riches of New Mexico and the beauty of fluores- pickeringite MgAl2(SO4)4-22H2O white-violet brightwhite- Guadalupe County cent minerals. violet The classic mineral producing localities of prehnite Ca2Al2Si3O10(OH)2 none yellowish- Sierra Blanca, New Mexico are well known; however, their flu- violet Lincoln County orescent counterparts have been relatively unex- rhodochrosite MnCO3 deep-pink pink Dictator mine, Cuchillo plored. It will come as no surprise that in most Negro district, Sierra cases the localities are the same. Nevertheless, County the fluorescent mineral collector should be aware sepiolite Mg4Si6O15(OH2)-6H2O dull-violet blue-violet Pinos Altos district, of three localities in particular. First, the Grant County Magdalena district, known primarily for its stilbite (Ca,Na,K)9[Al9Si27O72]-14H2O pale-yellow yellow Catron County apple-green smithsonite, is also a motherlode of titanite CaTiSiO5 yellow none Organ district fluorescent mineral species. Among the most tridymite SiO2 gray-pink gray Doña Ana County prevalent and attractive of known fluorescent zoisite (thulite) Ca2Al3(SiO4)3(OH) brick-red dark-pink Picuris district, Taos species found are allophane, anglesite, calcite, County cerrusite, fluorite, hemimorphite, hydrozincite, powellite, scheelite, smithsonite, sphalerite, and and franklinite, a zinc-iron-manganese oxide. willemite. Smithsonite from this area exhibits an STERLING HILL: YESTERDAY, TODAY, AND These three minerals are very rich in zinc and extremely wide range of fluorescent responses. TOMORROW, Richard Hauck, Sterling Hill are just a few of the 340+ minerals found in the Specimens have been found that fluoresce white, Mine and Museum, 30 Plant Street, district. This is about 10% of all those known and yellow, electric pink, purple, blue, red, and green Ogdensburg, NJ 07439 constitute a world record for the number of min- under short wave UV (257 nm). The long wave Sterling Hill is one of two mines that make up eral species from a single locality. Yet, zincite and UV (365 nm) response is generally a dull yellow. one of the most renowned mining districts in the franklinite are nowhere else mined outside the Unfortunately, the famous apple-green speci- world. Who would think that the mineral district. Willemite is found in very limited quan- mens have not been found to produce a signifi- deposits at the Sterling mine and its sister mine tities scattered around the globe. Besides the cant response. Second, the Picuris district, which in nearby Franklin would be one of the great richness of the ore, many of these minerals fluo- includes the Harding pegmatite, is also an excel- geological mysteries known to earth science resce. Again, this is a world record of at least 80 lent source of fluorescent mineral specimens. today? They exist in the Skylands of New Jersey, species that are fluorescent—more than any sin- The fluorescent species found include albite, just an hour from midtown New York. gle place on Earth. andalusite, bertrandite, bityite, calcite, eucryp- The Sterling mine is named for William The Sterling Hill mine closed for a variety of tite, fluorapatite, fluorite, kyanite, orthoclase, Alexander, Lord Sterling, who owned the prop- reasons in 1986. When this mine closed, it meant phlogopite, scheelite, spodumene, uranophane, erty from 1761 to 1776 and attempted to smelt the end of all underground mining in the State of zircon, and zoisite. Third, is the Iron Mountain the local ores. Dutch prospectors and the Lenni New Jersey. The Sterling Hill Mining Museum No. 2 district in Sierra County. This tungsten- Lenape Indians probably knew about the was established in 1989 and opened to the public magnetite skarn deposit has a number of inter- Sterling Hill orebody much earlier, which on August 4, 1990. The museum has been listed esting fluorescent mineral species that include cropped out in plain sight above the Wallkill on the Register of Historic Sites since 1991. The calcite, fluorite, helvite, powellite, scheelite, River. museum continues today as a non-profit founda- smithsonite, willemite, and zoisite. The Franklin–Sterling Hill mining district rep- tion. The museum is also a Mines, Metal, and In addition to the fluorescent mineral species resents two centuries of American mining histo- Men Site. found within New Mexico, there are a large ry and technology, mining law, and the earth sci- number of minerals from other localities around ences. It was not until after the perfection of ore- the world known to be fluorescent. Examples of dressing techniques in the early 1800s that min- ARAGONITE PSEUDOMORPHS OF PUER- these have not been found in New Mexico and ing the deposits became economically feasible. TO DE LUNA, GUADALUPE COUNTY, should serve as a focus for the future fluorescent The ore mined in the district was primarily NEW MEXICO, Dale G. Wheeler, 9000 mineral collector. zinc ore and consisted of the minerals known as: Trumbull Ave. SE, Albuquerque, NM 87123, zincite, a zinc oxide; willemite, a zinc silicate; (Location 6 on index map)

24 NEW MEXICO GEOLOGY February 2001 Among the many descriptions to be found of and others. As the seawater becomes trapped, Replacing mineral after Replaced mineral aragonite, none is more challenging than that evaporation sets in. As the volume of water is Calcite Aragonite, celestite given by Frederick H. Pough (1960, pl. 22) in his reduced, dissolved salts become more concen- Gypsum Anhydrite, aragonite book, A Field Guide to Rocks and Minerals, where trated. If the volume of water is reduced by Dolomite Aragonite he describes a variety of aragonite from New evaporation to approximately half, salinity is Off the Yeso–Fort Sumner Highway (US–60) to Mexico as “a pseudomorph after a trilling.” doubled, with calcium carbonate and iron oxide the north, Pecos “diamonds” may be found that Stuart A. Northrop (1959, p. 117) mentioned in being precipitated. As the original volume of are definitely quartz dolomite paramorphs. Did his book, Minerals of New Mexico, “early settlers seawater is reduced by evaporation to approxi- the dolomite extend into the Santa Rosa used them as sad-iron rests.” The specimens mately 20%, gypsum is deposited. It is estimated Formation? Yes, according to Kelley (1972). from Puerto de Luna can be reddish brown, that 25 mi of seawater would be required to yield Crystallography—In a review of aragonite, cream, or washed-out green; with full six-sided 100 ft of gypsum. Sinkankas (1964) states that an orthorhombic or partial (rotten) forms; displaying roses, light- The evaporating basin must have been repeat- crystal is uncommon. Sinkankas further brown posts, and six-sided posts, with six-sided edly replenished during a very long period of describes the crystals as short to long, prismatic micro1 rosettes all over. The specimens range evaporation under fairly constant climatic condi- along the c-axis, in six-sided prisms, nearly from ⁄8 inch to 4 inches in height and from 6 to 8 tions of aridity and rapid evaporation. The great hexagonal in cross sections, and terminated by a inches in width with varying weights. salt, gypsum, and anhydrite deposits of the pair of faces making a wedge. Practically all crys- I first went to the sites in 1959 while visiting world were formed during the Silurian, about tals are twinned along the plane m {101}, forming my parents in Santa Rosa, New Mexico. They 400 m.y. ago, and the Permian, about 200 m.y. sixling prisms, nearly hexagonal in cross sec- were managers of the Sun ‘n Sand Motel. Mom, ago. The salt deposits of New Mexico are tions. a rockhound, took advantage of the opportuni- Permian; hence, it is believed that formation of Pough (1960) describes the crystal shape as ties offered to get out in the area. Mom and Dad beds ranged from the Permian to the Triassic. trillings (three intergrown individuals), com- would have a few specimens at the motel desk Within the Upper Triassic Santa Rosa Formation mon, and looking like short hexagonal prisms or for guests to admire or “swap for” as rock- are bands of dark, reddish-brown mudstone. hexagonal plates. Re-entrant angle visible in hounds do, and most of the specimens were Between these are the layers of gypsum. As fresh, sharp crystals in the center of each appar- accepted as aragonite based on Pough's (1960) reported by Hurlbut (1970), “the sequence of ent prism of these pseudohexagons and stria- description. Only one negative comment was deposition of oceanic salts is as follows: first, cal- tions on the apparent base disclose the three ever made, and of course remembered, when cium carbonate and iron oxide; next, gypsum individuals. Mom was accused of going out and making and anhydrite; then, sodium chloride; and final- Sinkankas (1964) also discusses “cyclic and them! Initially, through my parents’ influence, I ly, salts of potassium and magnesium.” The arag- penetration twins,” which produce misleading developed many questions like: onite pseudomorphs are weathering out of the shapes resulting in a determination of a crystal (1) Are these pseudomorphs calcite after arag- vertical banks at all levels and down on and into shape in one form when actually it is in another. onite, dolomite, and/or gypsum because they the floor of the dry creek bed. In an example, he shows an aragonite twin with are found in lengthy gypsum beds? Mineralogy—sedimentary, deposition from the impression that it is a hexagonal crystal being (2) Why are the specimens all perfect or near water movement. The loose sediment is cement- viewed. However, on examination small re- perfect at one site (southeast), and why are they ed into coherent solid rock by any of several entrants were seen. Because a penetration twin is rotten in the same formation to the northwest? processes—one of which is crystallization. one in which two or more complete crystals seem (3) Is this an “evaporite deposit,” and if so, is it Sandstone, shale, and carbonate rock constitute to cross through each other with each crystal similar to that of the Great Salt Plains at Jet, the most abundant rock. having a common center, as in staurolite, it is Oklahoma? Carbonates are formed when carbon dioxide believed that a parallel layer of growth on top of (4) Are the specimens old or new in terms of contained in water combines with oxides of cal- an existing circular form or at right angles to per- historical geology? Are they still growing? cium and magnesium. Many sedimentary rocks pendicular (Santa Rosa pseudomorph posts) (5) What is the chemistry and crystallography are nonclastic—formed by intergrowth of crys- would make these a penetration twin. However, (floating atoms, exchange, and changing crystal tals. Nonclastic rocks can be formed from mater- perhaps the temperature-pressure equation dur- shape from orthorhombic to hexagonal)? ial directly precipitated. Again, we have our car- ing the forming led to crystals cementing them- If a pseudohexagonal twin seems to pierce bonate friends including calcite crystallizing in selves to each other with the outer layer being another pseudohexagonal twin at an angle in the the hexagonal , aragonites of the gypsum covering the original joining line. same specimen, is this a true penetration twin? orthorhombic system, and dolomite also in the Are the crystals still growing? I believe they Location—southeast of Santa Rosa, Guada- hexagonal system. After calcium carbonate has are just “weathering out.” lupe County, New Mexico, near the historic town accumulated, it becomes recrystallized or other- References site of Puerto de Luna on the Pecos River. North wise consolidated into indurated rock (a process Hurlbut, C. S., Jr., 1970, Minerals and man: Random and west of the Pecos River bridge, a layered of the hardening of a rock material by the appli- House, pp. 118, 121, 122. formation is littered with clear plates of selenite; cation of heat or pressure or by the introduction Kelley, V. C., 1972, Geology of the Fort Sumner all specimens are rotten. Whole specimens are of a cementing material). sheet, New Mexico: New Mexico Bureau of found weathering out of gypsum red beds The aragonite pseudomorphs at Puerto de Mines and Mineral Resources, Bulletin 98, 55 pp., approximately 1 mi to the south and east in an Luna are definitely trillings as defined by Pough 2 sheets, scale approx. 1:190,000. always-dry, trenched, soft floodplain deposit (10 (1960). For aragonite to form it must be in a prop- Northrop, S. A., 1959, Minerals of New Mexico: ft deep by 30– 50 ft wide). The exposure of mate- er environment not only for its development but University of New Mexico Press, 665 pp. rial extends for at least 1 mi. The collecting of also for it to maintain its stability. The growth is Pough, F. H., 1960, A field guide to rocks and min- specimens is done on private land, and due to not always steady. The slightest impurity may erals: Houghton Mifflin Company, 317 pp. Sinkankas, J., 1964, Mineralogy for amateurs: Van the severe fire danger in recent years on both cause uneven growth resulting in “weird” crys- Nostrand Reinhold Company, p. 371. grasslands and in forests, it is doubtful if permis- tal shapes with perhaps over development of sion could be obtained to cross this area. some crystal faces and partial formation of oth- Further reading Ford, W. E., and Dana, E. S., 1898 and 1922, Geology—Triassic sandstone and siltstone ers (rotten?). The formed aragonite is altered Compound or twin crystals; in A textbook of min- consisting of multicolored sandstone, conglom- when some quirk in the environment changes— eralogy: John Wiley & Sons, Inc. erate, locally with limestone pebbles of the Santa when it loses its chemical composition to a com- Levin, H. L., 1978, The Earth through time: W. B. Rosa Formation, capping reddish-brown and tan bination of factors (temperature and pressure, Saunders Co., pp. 335, 374, 377. sandstone with gypsum and dolomite in the loss of water, loss or gain of chemical elements) Sanbom, W. B., 1976, Oddities of the mineral world: lower part of the Grayburg and Queen For- or when its chemical composition changes but its Litton Educational Publishing. “Pseudomorphs”. mations. Advancing and receding warm seas still remains the same. Then, it is present in Permian through Cretaceous time known as pseudomorph. The pseudomorph at formed shallow lagoons in southeastern New Santa Rosa is one whose chemical composition RAINDROPS ON ROSES AND WHISKERS Mexico. Thin limestone, evaporites, and red beds has changed twice. Virgil Lueth analyzed five ON SILVER: THE TRUTH (?) BEHIND PRI- were deposited. Connections of the lagoons specimens by X-ray diffraction to determine MARY ACANTHITE, Bruce Geller, Advanced became so severely restricted that when the whether they are calcite, dolomite, or gypsum, Geologic Services, 700 Vista Lane, Lakewood, waters evaporated, a great thickness of gypsum with all specimens retaining the pseudohexago- CO 80215, and Bob Jordan, 315 Iowa Drive, and salt was left. nal form of aragonite. In the common table of Golden, CO 80403 Seawater contains 0.14% calcium sulfate, 0.01% pseudomorphs relating to this paper three exam- Over 120 yrs ago, argentite was first reported in calcium carbonate, 0.32% magnesium chloride, ples are given: Colorado (Endlich, 1878). Since that time, all of

February 2001 NEW MEXICO GEOLOGY 25 the argentite studied in Colorado has been found most other minerals do. to be acanthite, the monoclinic form of silver sul- Disappointingly, a literature search combining REVISITING THE SAN PEDRO MINE: A HIS- fide, which is the stable form of Ag2S below the terms primary or arborescent, or acicular or den- TORICAL AND MINERALOGICAL PER- 177(?)°C. In Colorado, acanthite is usually found dritic or needle or hair or tree with acanthite, or SPECTIVE, Jerry Simmons, 1463A State Rd 344, in secondary enriched zones of epithermal sil- argentite failed to obtain any matches. The com- Sandia Park, NM 87047 ver-base metal deposits such as the limestone bination of monoclinic and acanthite only found (Location 7 on index map) replacements at Leadville and Aspen or the veins four marginally useful references. The combina- Historically, the San Pedro mine represents a at Creede; however, it has been reported from at tions of habit or form or morphology and acanthite grand view of New Mexico’s history. Five eras of least 27 additional districts and undoubtedly proved slightly more productive. activity by differing or mixed ethnic groups occurs sporadically throughout the state (Eckel What many authors really mean when they depict this once thriving mining scene of north- et al., 1997). use the term primary acanthite is acanthite that central New Mexico. The first of these eras saw Collectable and much sought after silver-bear- crystallized as itself, rather than forming as a the Native Americans foraging for big game and ing minerals such as native silver, Ag-sulfides paramorph after argentite, the higher-tempera- materials for utensil use. The second era, the (primarily acanthite, stromeyerite, and jalpaite), ture, isometric form of Ag2S. However, the use of Colonial Spanish Period, would be represented Ag-sulfosalts (primarily pyrargyrite, pearceite, the word primary as a descriptor for acanthite is by Spanish royals looking for profitable areas to matildite, polybasite, schirmerite, proustite, and actually a misnomer because much acicular mine precious metals. During the subsequent stephanite), Ag-tellurides (primarily hessite, pet- acanthite is formed by supergene processes after settlement of land and the use of land grants (the zite, and sylvanite), and Ag-halides (primarily some other Ag phase. Use of morphological third era, called the Mexican Period), Spanish bromargyrite-) are known from terms such as acicular, arborescent, or needle- shepherds, in their daily routine of herding goats many mining districts within Colorado (Eckel et like are far clearer in describing not only the and sheep, discovered float gold in both the al., 1997). The most famous of these districts form of the acanthite in question (monoclinic), Ortiz and San Pedro Mountains. The fourth era, include: Caribou, Gold Hill, and Ward in but also its genesis (independent crystallization which correlates roughly with the opening of the Boulder County; Georgetown–Silver Plume in and not paramorphic replacement after primary, Santa Fe Trail as a trade route in 1821, saw the Clear Creek County; Rico in Dolores County; isometric argentite). influx of eastern US citizens, merchants, mining Gold Brick in Gunnison County; Creede in Illustrations will be provided showing acicular specialists, and fortune seekers. Local as well as Mineral County; Montezuma in Park and acanthite from Colorado. It has been reported non-local companies vied for the right to mine Summit Counties; Aspen in Pitkin County; from at least seven other districts: Creede the profitable mineral values. This would be the Silverton in San Juan County; and Telluride in (Plumlee, pers. comm. 2000), Gilman (this time of greatest exploration and expansion of San Miguel County. study), Leadville (Raines, pers. comm. 2000), mining the state would experience. As the dis- Colorado's silver mining tradition dates back Rico (Chester, 1894), Ruby/Irwin (this study), covery of ore deposits became less frequent, the to 1864, when its first silver lode was discovered Silver Plume (crystals coating argentite and later final era, which began somewhere around 1938, "on Glacier Mountain, about a mile south of coated by pyrite), Silverman (this study), and involved only a few large businesses and many Montezuma" (Lovering and Goddard, 1950, p. Ward (crystals coating native silver, pearceite, small or local interest groups who were active at 123). Interestingly, samples from this district and galena; Eckel et al., 1997). the mine. Some of these ventures were profitable, were the catalysts for this investigation. The Further questions to be discussed include: Is whereas most were only marginally successful. samples are examples of high grade silver min- there anything unique to Creede, Leadville, The final pages of history for the San Pedro mine eralization, but they were unusual for two other Montezuma, Rico, Ruby/Irwin, Silver Plume, were opened in 1999 when the mine was sold to reasons. First, they contain microscopic arbores- and Ward that causes their deposits to generate a former local resident. Reclamation involving cent growths. Second, the fine growths were not acicular acanthite? Why wasn't the acicular acan- recontouring and reseeding of the old tailing noticed until a decade after they were collected. thite on the Montezuma specimens observed in piles; bat only entrances where major tunnels In fact, it is believed that they have formed since the field? How does acicular acanthite form? once existed; and no trespassing, hunting, or they were collected, similar to some polished Why doesn't acicular acanthite form on house- prospecting signs all give evidence to the closing sections studied from Creede (Raines, pers. hold silverware or jewelry? of a grand old mine and the opening of a new comm. 2000; Plumlee, pers. comm. 2000) and References era, which may include a museum. elsewhere (Mozgova et al., 1994). Chester, A. H., 1894, Acanthite from Colorado: Mineralogically, the San Pedro mine area, com- To confirm this last point, a trip was made in Columbia University School of Mines Quarterly, monly known as the New Placers district, has August 2000 to the mine where the specimens v. 15, pp. 103–104. produced 93 different mineral species. Of this originated in the early 1980s, the Burke–Martin Eckel, E. B., and others, 1997, Minerals of Colorado: large number of species the most common are mine, also known as the Bell, California, Meteor, Fulcrum Publications, Golden, CO, 665 pp. garnet (andradite), calcite, quartz, hematite Silver Wing, Sunburst, or Wing lode (Lovering, Endlich, F. M., 1878, Mineralogical report: cata- (specular), and chalcopyrite. Recent discoveries 1935). Many samples were taken from the exact logue of minerals found in Colorado; in Hayden, have added to these: tetradymite, ankerite, pow- 1980s stockpiles of mineralized material from the F. V., 10th Annual Report for 1876: US Geological ellite, smithsonite (pink), and amethyst Albany or Old Timer vein by three different min- and Geographical Survey, p. 138. sceptered Japan law quartz. Reports of brochan- eral collectors. Each collector found native silver Lovering, T. S., 1935, Geology and ore deposits of tite, molybdenite, talc, and fluorite (green and the Montezuma quadrangle, Colorado: US and various hypogene and supergene associates, purple) were verified. This assemblage of miner- Geological Survey, Professional Paper 178, 119 yet none found any of the arborescent growths. pp. als is not uncommon for this skarn-type deposit. Laboratory investigations using standard X- Lovering, T. S., and Goddard, E. N., 1950, Geology The fascinating aspect of collecting has been the ray diffraction failed to establish the identity of and ore deposits of the Front Range, Colorado: seemingly endless variety of forms of the com- the growths. Neither did comparisons with sil- US Geological Survey, Professional Paper 223, mon species. Current use of UV equipment will ver minerals observed in a talk given at last 319 pp. most likely reveal more new species. All current year's symposium by Regis and Regis (1999). Mason, B., 1997, Acanthite; in Gaines, R. V., and oth- collecting is with the new owner’s permission. However, scanning electron microscopy verified ers, Dana's new mineralogy: John Wiley and Planning is underway to put more San Pedro that they are acanthite and indeed delicately Sons, New York, p. 42. specimens in the Bureau's display and to devel- exquisite. In fact, the name acanthite “is from the Mozgova, N. N., and others, 1994, New growth of op a historical as well as a mineralogical muse- Greek for thorn, referring to the shape of the sulphides on the surface of polished sections: um at the mine site. crystals” (Mason, 1997, p. 42). International Mineralogical Association, abs. 16, One explanation why the X-ray diffraction p. 288. study proved fruitless is that acanthite is very Regis, A. J., and Regis, K. A., 1999, The ugly ores of sectile and does not pulverize well using a mor- silver—part II, a photo gallery: Twentieth Annual tar and pestle. Hence, it could not diffract the X- New Mexico Mineral Symposium, abs., pp. ray beam to produce characteristic peaks, as 20–21.

26 NEW MEXICO GEOLOGY February 2001