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Home , Agate, Agate (nuclear test), Almandine, Amethyst, Andradite, Beryl

summer 2016

Gemstones of New

leasing colors, shapes, durability, production. Native people used a Pand rarity are all characteristics of number of gem materials (, the that we call . shell, and ) in their ceremonial The quest for these stones has long objects and gemstones, specifically allured people. Gemstones have been (red, -rich found in many archeological sites, garnet) and (pale gem attesting to a long fascination with version of a called ), beautiful objects from the . We which have been found in the ruins continue to decorate ourselves with of their dwellings. Native American these objects as an expression of jewelry style is still based on the use status, or simply to enjoy something of turquoise and other stones, often beautiful. Many gemstones have a set in or strung in . long and complicated path from However, the most well-known where they are formed, in the earth, precious gems, , , to finally becoming a , , , and are poorly rep- pin, or other type of . resented in the state. Semiprecious Gemstones are minerals that stones like and its varieties have clarity (containing little to (, citrine, smoky or rose), no material interfering with the (the most common mineral passage of light), color (a desirable in the earth’s ), peridot, and , saturation, & tone), and a level (a -rich mineral) are of that resists abrasion more abundant. Turquoise is, by or chipping. When we think of far, the most iconic gemstones, we typically think of /gem material, as well as diamond, emerald, ruby, or sapphire, the classic, Kelly which are cut (faceted) and placed in (bottom photo). A thorough discus- rings, , pins, and sion of these minerals is beyond (top photo). However, another class of the scope of this article, so we will gems, called gem materials, includes focus on other gemstones and rocks or minerals that lack the clarity gem materials from the Land of and sparkle of gemstones, but are Enchantment. used for adornment because of pleasing color or pattern. Turquoise, Historical Accounts of , , and other colored Gems in New Mexico rocks and minerals represent gem Top—Gemstones cut & polished for jewelry, from the Mineral When the Spanish conquistadors materials, which are usually carved Museum gemstone collection. Back row, left to right: amethyst, explored New Mexico, they were citrine, rose quartz, ; middle row, left to right: aquamarine, or “cabbed”, worked into a disk or , ; front row, left to right: heliodor, rubellite, seeking , silver, and gemstones. oblong smooth oval object called a . A number of their reports mention (bottom photo). Bottom—Popular gem materials used in carvings, slabs, & the presence of gemstones, usually , from the Mineral Museum gemstone & mineral highlighting their abundance Introduction collection. Back row, left to right: smithsonite sphere, slab; middle row, left to right: ricolite cabochon, (showing that exaggeration is not New Mexico is blessed with a picture slab, red cabochon; front row, left to right: something invented by modern wide variety of gemstones and has turquoise cabochon, malachite/ cabochon, advertisers!). One of the first a long history of gemstone use and teardrop cabochon. Photos by Virgil Lueth. accounts was by Cabeza de Vaca,

Published by the New Mexico Bureau of and Mineral Resources • A Division of New Mexico Tech Bedded Large-scale production found above diatreme vents. Erosion pyroclastics of gemstones and gem following the eruption can expose the material has been attempted diatreme as a high-standing landform, a Maar in New Mexico, particularly well-known example in New Mexico being for turquoise. There has Shiprock. Peridot, red pyrope garnet, and been a general lack of bright green chrome are the most systematic exploration for other types of common examples of diatreme-related Diatreme gemstone deposits because the costs of gems in New Mexico. The Volcanic development usually are greater than any on the * has numerous indicated profit from production. occurrences of these gems. Peridot, pyrope, The small size of the deposits, and chrome diopside weather from the capricious distribution and host , called , and accumulate quality of stones, and on the surface or are concentrated on ant market demands conspire hills by the industrious insects. The gems to make New Mexican can be easily collected, and are packaged gem only a and sold in local trading posts. At these gift small scale affair. Most shops, the gems are often given fanciful deposits in our state are names like, “emerald, beryl, green garnet found and developed or Job’s tears” for peridot, and “, by mineral collectors or Rocky Mountain, or New Mexico ” weekend gem hunters. for pyrope. Another famous peridot locality is Schematic diagram of a funnel-shaped Gemstone Deposits of , a maar crater in the diatreme at depth and a broad shallow crater, Potrillo Volcanic Field of Doña Ana or maar, at the surface. Shiprock represents New Mexico an exposed portion of a diatreme, while County*. At Kilbourne Hole, fragments Kilbourne Hole is an excellent example of a Gemstones form in a wide variety of of volcanic rocks, called bombs, that were maar. Photo shows xenocrysts of light green environments, from the earth’s partially ejected from the vent during a very ener- olivine (peridot) and dark green chrome molten , to the earth’s surface, getic and explosive eruption, can include diopside that were carried from the mantle through alteration of volcanic rocks. peridot xenocrysts (diagram upper left). to the surface during an explosive eruption. The unique environments that allow Specimen is 8 cm across. Photo by Shari Kelley. These bombs are scattered about the crater gemstones to form in the earth’s crust and and have been collected for over 100 years. describing shaped like arrow mantle result in their rarity. A multitude A rather unique occurrence of volcanic- points. Quartz known as “Pecos of physical processes and conditions (e.g. related gemstones can be found at Valley ” were first described by temperature & pressure regime, presence Park in Catron County*. Hosted in a Don Antonio de Espejo in 1583. Carrera or absence of fluids, trace elements, etc.) flow are large, clear, yellow reported the presence of “” in must combine in particular ways in order to crystals of -rich feldspar the that turned out to produce a beautiful gemstone. Gemstones that grew in the chamber from be another blue mineral, . Reports can be grouped, or classified, based on their which the basalt was erupted. These stones, of emeralds, rubies, and diamonds, all environment of formation. Several such formally known as , have been misidentified, persisted through the environments, which will be defined and collected and faceted by gem hunters only Mexican period and into statehood. discussed below, include—volcanic-related, fairly recently (probably only since the The first gem minerals advertised from pegmatitic, hydrothermal, metamorphic, 1960s), and were hence not mentioned in New Mexico, in early mineralogical maga- and sedimentary. In the following sections, the first two editions of Minerals of New zines, were peridot and pyrope. An article locations of gemstones marked with an Mexico. These gems are a pleasing honey- published in The Mineral Collector in asterick can be found on the map. yellow color, and a few rare stones display 1895 titled, “American Jewel Mines” touts a color similar to found New Mexico gem occurrences: “…The Volcanic-Related in Oregon. fine aquamarine beryl has also come quite Most volcanic-related gemstones Diamonds be found in diatremes, extensively from Stoneham, . This originate deep in the earth’s mantle. having been transported to the surface in gem, or rather mineral, abounds in New These crystals, called xenocrysts (foreign a similar way to the gemstones described Mexico and Arizona where it was mined by crystals), form at great depth 150–650 above. Diamonds are typically associated the early , and later by the Spaniards kilometers (93–403 miles), and are carried with a rock type called (a and Pueblo Indians. The demand for it is to the surface rapidly during very explosive potassic ), thought to erupt good and the supply never keeps pace with volcanic eruptions that form features from great depths extremely rapidly, the sales. The finest in the world called diatremes and maars. Diatremes are possibly because the magma contained funnel-shaped volcanic throats, or con- come from these latter Territories. high concentrations of CO2, driving the are mined there, or rather taken from ant duits, filled with fragmented (brecciated) explosive eruption. Some magma composi- hills and scorpion nests by the Indians and volcanic rocks, as well as xenocrysts derived tions found in the Navajo Volcanic Field soldiers.” Once again it appears exaggera- from the mantle and/or rocks from the rocks are similar to , but no tion transcends reality concerning New crust through which the magma erupted substantiated occurrence of diamond has Mexico gemstones. (diagram above). Maars are shallow craters ever been documented in New Mexico. new mexico earth matters 2 summer 2016 However, one of the first great gem hoaxes Raton of the west had a New Mexico connection, Tierra the Ralston diamond hoax (for more Amarilla information, please see the links provided at the end of this article). 25 Los Alamos Santa These rocks are very coarse-grained and Fe form during the last stages of magmatic Las Vegas Gallup crystallization or from high-grade meta- 40 Bernalillo morphism. As magma crystallizes, some less Grants Albuquerque 40 abundant (trace) elements (, beryl- lium, , , ) are Santa Rosa excluded from the structures of com- Los Lunas Estancia mon minerals. As crystallization continues, they concentrate in the residual (left over) magma. When concentrations become great enough, unusual minerals characteristic Socorro of pegmatites begin to form and can grow Reserve quite large from 2.5 centimeters to over

10 meters (about one inch to over 32 feet)! 25 These include , beryl, topaz, apa- Truth or tite, and . New Mexico has abundant Consequences pegmatites, many of which have produced Silver small amounts of gemstones and gem mate- City

rial. Quartz crystals can also grow to large Carlsbad Las sizes in these settings and impurities within Cruces the crystal give rise to the different varieties 10 of smoky, amethyst and clear rock crystal quartz. New Mexico pegmatites are typically Proterozoic (around 1 billion years old) or Tertiary (around 30 million years old), and 0 50 mi their distinct described below 0 80 km have produced different suites of gemstones. Pyrope (garnet), Navajo Volcanic Field Yellow , Organ Mountains Northern New Mexico Proterozoic pegmatites have been mined and studied the Peridot, Kilborne Hole , Rabb Canyon most, but pegmatites occur in igneous and metamorphic rocks throughout the state. Yellow Plagioclase, Pueblo Park Amethyst, Ladron Mountains Beryl is the main gemstone produced and runs the gamut of varieties; (morgan- Morganite (beryl), Harding mine Irridescent (garnet), ite), clear (goshenite), blue (aquamarine), San Pedro Mountains Emerald (beryl), Picuris Mountains and green (emerald). Gem-quality beryl Andradite (garnet), Picuris Mountains from this state is actually quite rare. Most Rock Crystal Quartz, Petaca District are cloudy and pale, probably because , Taos they crystallized too deep in the crust and , Sierra Blanca too slowly to generate good clarity. Good gem beryl (mainly morganite) has been Map of New Mexico gemstone localities. NOTE: Photos by Virgil Lueth. produced from the Harding *, as well as some aquamarine from the Petaca and Las Vegas (Elk Mountain) areas. Other gem material from the northern known stones of kunzite exist, but the Emerald was found recently in the Picuris New Mexico pegmatites is the rose-colored potential remains for their discovery. Range* although the crystals are cloudy. lepidolite, which in some deposits The Tertiary age pegmatites have Gem-quality quartz can also be found, the forms dense masses and is used in carvings produced much better gem quality material, most famous from the Petaca District*. No and cabochons (gem group at bottom on first although the gems are the more common gem-quality have been found, page). , another -bearing varieties of quartz, feldspar, and apatite. even though the correct chemical variety mineral, is found in some deposits usually These crystallized much faster and (elbaite) has recently been documented from as flesh-colored blades. When clear and closer to the surface than the older pegma- the Rociada area. Like the other gemstone colored pink or green, this mineral is known tites, forming better gemstones. The finest occurrences, apatite, topaz, and zircon are by the gem names kunzite and hiddenite, smoky quartz in New Mexico comes from also cloudy and not suitable as gems. respectively. Some New Mexico spodumene miarolitic (giant bubbles in ) has a pink color, but remains cloudy. No deposits of Sierra Blanca*. Occasionally, new mexico earth matters 3 summer 2016 material has been cabbed from deposits and occasionally form gemstones and near Silver City and in the . gem materials. The heating and squeezing When hydrothermal react with of mud-rich sedimentary rocks typically impure , a unique metamorphic results in the formation of alumino- rock called can be formed. These minerals, specifically , , rock bodies may contain large masses of and , which all may qualify garnets, ranging from ( as gemstones or gem materials. Most rich) to andradite ( and calcium rich) metamorphic-derived gemstones of New in composition. A rare clear garnet, called Mexico are associated with the formation , produces a gemstone with of Proterozoic pegmatites. The most Gemstones of Raab Canyon pegmatites. Blue a characteristic (a measure of well-known of these is viridine (green to silver-white moonstones. Photo by Virgil Lueth. splitting white light into its spectral colors) andalusite) in the Pilar and Petaca areas. greater than diamond. Demantoid-like Crystals of kyanite are found in places, yellow to crystals of apatite in miaro- stones have been produced from the but are not clear enough to constitute litic cavities from the Organ Mountains* gem-quality kyanite. Fibrous sillimanite of attain a size and clarity that allow them to varying color produces the gem material be faceted into gems. fibrolite, known to gem cutters for over A unique pegmatite body at Rabb 100 years, and has come from the Truchas Canyon in Grant County produces gem area. Likewise, near-gem-quality andradite, (a high temperature feld- (iron-bearing), and spessartine ) known as moonstone*. Microscopic garnets have been collected from the lamellae (thin layers) of sanidine and northern mountains*, but remain disap- ( feldspar) create a grating effect that pointingly cloudy despite their beautiful generates the “glow” of moonstone when root beer-red to orange-yellow colors. held at certain orientations in the light. The Perhaps New Mexico’s most famous color of moonstone at this locality ranges metamorphic gem materials are the from blue to silver-white (above). The Rabb Smoky amethyst. Photo by Virgil Lueth. of Hondo Canyon, near Taos*. Canyon pegmatite also produces a fine smoky amethyst that may be found as rough Apache Hills near Hatchita. Occasionally, masses and then faceted into purplish-black complex intergrowths of andradite, gros- gemstones (right). sular, and calcite create an iridescent garnet Gem quality beryls, albeit small, were that is highly sought after. Garnet Ridge, uncovered during the mining of molyb- near San Pedro*, is famous for producing denum at the Questa Mine in northern this type of stone that may be fashioned New Mexico. These gemstones occurred into cabochons or directly polished, and in the pegmatite-like bodies associated can yield a “cat’s eye” effect. with the Tertiary igneous intrusions at the Hydrothermal fluids moving through mine. Microscopic grains of green emerald volcanic rocks, mainly rhyolite, can and blue aquamarine are clear and would produce gemstone deposits of red beryl Minerals commonly not used as gemstones be considered gems if they attained a and topaz. These deposits have been due to softness, inclusions, and/or structural sufficient size. Now that the mine is closed, famously developed in but remain to defects. From left to right: barite, , and the potential for quality stones has be discovered in New Mexico. Small red . Photo by Virgil Lueth. disappeared. beryls and topaz are found in the Black Range of Sierra County associated with The most prized specimens are red-brown Hydrothermal deposits. So far, the stones have proven “fairy crosses,” interpenetrating twins that Hot derived from crystallizing too small to be fashioned into gems but resemble a cross. These are often mounted magma and/or deeply circulated and the potential exists for more significant in necklaces and sold around the Taos area. heated water, scavenges elements from deposits. Similarly, the at East They are never clear and may be coated the rocks it flows through and produces Grants Ridge in Cibola County, contain with mica, which requires cleaning most ore deposits of gold, silver, and beautiful crystals of topaz, aquamarine, and to make them presentable. Both staurolite base metals. Occasionally, gemstones are spessartine (-bearing) garnet that and metamorphic-derived garnets are created as part of the mineralizing process, are collected for micromineral specimens, typically cloudy due to mineral inclusions, mainly comprising the quartz varieties but remain too small to into which are present because these minerals smoky and amethyst. Some of the finest gemstones. envelop other mineral grains during their amethyst gems have been produced from formation. veins associated with fluorite in the Ladron Metamorphic Mountains near Socorro*. Similar, but less Under extreme heat and pressure Sedimentary spectacular, amethyst and smoky quartz has rocks are metamorphosed (meaning “to The low temperature and pressure envi- been found from deposits near Bingham. change form”). Minerals transform in ronments of sedimentary rocks precludes Banded white and purple quartz gem response to these changing conditions the formation (contintued on page 6) new mexico earth matters 4 summer 2016 bureau news Bureau Bulletin 161 Awarded Frye Memorial Award The recently published New Mexico Bureau of Geology and Mineral Resources Bulletin 161, “Geology and Hydrology of Groundwater-Fed Springs and Wetlands at La Cienega, Santa Fe County, New Mexico” http://geoinfo.nmt.edu/publi- cations/monographs/bulletins/161/, has received the Johnathan C. Frye Memorial Award from The Geological Society of America and the American Association Taos County Honors Peggy Volume 16, Number 2 of State . The Frye Award is Johnson with Community presented annually for the best publication Published twice annually by the Service Award New Mexico Bureau of Geology in the field of environmental geology Taos county commissioners honored Peggy and Mineral Resources Johnson with a Community Service Award Matthew J. Rhoades, CPG, RG NEW MEXICO BUREAU OF GEOLOGY AND MINERAL RESOURCES State and Director for her 20 years of water-science work in a division of Geology and Hydrology of Groundwater-Fed Springs and Taos County. She has worked on about a New Mexico Institute of Wetlands at La Cienega, Santa Fe County, New Mexico dozen major hydrogeology studies for the Mining and Technology

Peggy S. Johnson, Daniel J. Koning Stacy S. Timmons, and Brigitte Felix county over the years. Dr. Stephen G. Wells President 801 Leroy Place Socorro, New Mexico 87801-4750 Bureau Albuquerque office 2808 Central SE Albuquerque, New Mexico 87106 (505) 366-2530 HYDROGEOLOGY

Bulletin 161 2016 Board of Regents Ex Officio Susana Martinez published by a state geological survey or Governor of New Mexico by GSA during the past three years. The Rockin’ Around New Mexico, Dr. Barbara Damron Secretary of Higher award will be presented to the authors of Las Vegas, New Mexico the study, Peggy Johnson, Daniel Koning, Appointed Stacy Timmons, and Brigitte Felix, all of Rockin’ Around New Mexico, a geology Deborah Peacock the New Mexico Bureau of Geology and workshop for teachers, was held in Las President, 2011–2016, Corrales Mineral Resources, at the GSA annual Vegas on July 6–8, 2016. The 27 teachers Jerry A. Armijo Secretary/Treasurer, 2015–2020, Socorro meeting in September 2016. who participated gained field geology experience at locations near Las Vegas, David Gonzales Bulletin 161 focuses on the geology and 2015–2020, Farmington hydrology of the La Cienega wetlands, where they learned about the uplift process Donald Monette located near Santa Fe, New Mexico. La that created Hermit Peak, and Montezuma 2015–2018, Socorro Cienega’s springs and wetlands are impor- Hot Springs. Other field trip stops included Myissa Weiss, student member tant hydrologic, ecologic and cultural a recent landslide and a spectacular exposure 2015–2016, Farmington resources, and provide many beneficial of the Great Unconformity. Editors water-related functions. In the classroom, Next Generation Nelia Dunbar Findings from this investigation Science Standards were introduced. Gina D’Ambrosio emphasize possible solutions that may Teachers worked with several seismic mod- Richard Arthur allow hydrologic resilience and successful els to explore faults and structural stability Layout Design & Graphics preservation of the important wetland in buildings. After a presentation on seis- Gina D’Ambrosio resources at La Cienega. These solutions mic hazards and safety, and an update on Leo Gabaldon focus on reducing groundwater depletions the 2011 Christ Church, NZ earthquake Visit our website at: geoinfo.nmt.edu in the Ancha Formation and supporting recovery efforts, teachers practiced the a positive wetland water balance. Possible Drop, Cover, and Hold On! earthquake Earth Matters is a free publication. remedies include managing groundwater For subscription information please call safety drill. This workshop was sponsored (575) 835-5490, or e-mail us at withdrawals, managing unwanted invasive by New Mexico Bureau of Geology, New [email protected] vegetation, and developing effective Mexico Department of Homeland Security storage projects. Cover photo of Chimney Rock, New Mexico Emergency Management, and New © Matthew Zimmerer Mexico Mining Association. new mexico earth matters 5 summer 2016 New Mexico Bureau of Geology & Mineral Resources NONPROFIT ORGANIZATION New Mexico Institute of Mining & Technology U.S. Postage 801 Leroy Place PAID Socorro, New Mexico 87801-4750 Return service requested permit no. 1888 Albuquerque, NM

gemstones of new mexico (continued)

of many gemstones. This environment does at mineral shows to collectors of New Links of Interest produce some gem materials, mostly colored Mexico material. Nevertheless, small-scale silica materials (, jasper, and agate), collecting and faceting of gemstones and Ralston Diamond Hoax articles: and variably-colored that may gemstone materials is a hobby that brings http://www.smithsonianmag.com/ be fashioned into cabochons (bottom gem pleasure to many of the state’s residents history/the-great-diamond-hoax-of-1872- group page 1). Occasionally, facetors will and visitors. 2630188/?no-ist practice their skills and fashion beautiful, but fragile gemstones from calcite, dolomite, —Kelsey McNamara and Virgil Lueth http://www.history.com/ barite and fluorite (see photo of three gems this-day-in-history/ page 4). the-great-diamond-hoax-is-exposed Kelsey McNamara is the new curator at the Future of Gemstone Exploration in New Mexico Bureau of Geology Mineral New Mexico Museum. Prior to joining the bureau she Correction: In the Winter 2016 issue Although New Mexico has many gem- worked as a hydrogeological field techni- of Earth Matters, we highlighted a book stone localities, these have never proven to cian, a geology field camp instructor, and a published by Dana Ulmer-Scholle and Peter be a major source of revenue. New finds freelance geologist. Scholle. In that writeup, we suggested that may still be discovered by collectors and the book had won an award, which was prospectors, but probably never on a scale Virgil Lueth is the director of the New incorrect. large enough to support significant mining Mexico Mineral Museum as well as operations. Most likely, as has been the Senior Mineralogist/Economic Geologist at case in the past, specimens will be sold the bureau.

For more information about the bureau and our publications: Visit our website at http://geoinfo.nmt.edu Call (575) 835-5490, e-mail us at [email protected], or visit our Publications Office in our new location at the corner of Bullock and Leroy on the campus of New Mexico Tech, 801 Leroy Place, Socorro, NM, 87801. new mexico earth matters summer 2016