DOCSLIB.ORG

Black Diamond Pegmatite Custer County, South Dakota

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Black Diamond Pegmatite Custer County, South Dakota Diamond-drilling Exploration of the Beecher No. 3- Black Diamond Pegmatite Custer County, South Dakota GEOLOGICAL SURVEY BULLETIN 1162-E Diamond-drilling Exploration of the Beecher No. 3- Black Diamond Pegmatite Custer County, South Dakota By J. A. REDDEN CONTRIBUTIONS TO ECONOMIC GEOLOGY GEOLOGICAL SURVEY BULLETIN 1162-E UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1963 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.C. CONTENTS Page Abstract___________._______________________.__ El Introduction.___________________________________ ________ 1 Description of pegmatite units_____________________ _____.-__ 2 Structural geology_________________________________________________ 9 Economic appraisal of the exploration____________________________ 10 References. ___ __________________________ 11 ILLUSTRATION Page PLATE 1. Outline map and sections, Beecher No. 3-Black Diamond peg- matite______________________________________ In pocket TABLE Page TABLE 1. Diamond-drill logs, Black Diamond pegmatite.____________ E3 m CONTRIBUTIONS TO ECONOMIC GEOLOGY DIAMOND-DRILLING EXPLORATION OF THE BEECHER NO. 3-BLACK DIAMOND PEGMATITE, CUSTER COUNTY, SOUTH DAKOTA By J. A. REDDEN ABSTRACT Diamond-drilling at the Beecher No. 3-Black Diamond pegmatite, Ouster County, S. Dak., has provided information that modifies and supplements findings reported previously (Redden, 1959). Two zones not exposed at the surface were found during the drilling: a quartz-albite-perthite-muscovite-pegmatite zone and a quartz-albite-perthite-spodumene pegmatite zone. Previous concepts of the structure near the surface require no significant change, but the new data make possible a greatly improved interpretation of the structure at depth. The most notable change is the recognition of a narrow constriction in the pegmatite at a depth of 60 to 100 feet. The drilling results are not encouraging in an economic sense. The beryl-rich deposit exposed at the surface was not recognized in the drill core, but the quartz- albite-perthite-muscovite pegmatite zone is the most favorable for further ex­ ploration. The known beryl deposits are all above the newly discovered constric­ tion and along a low-plunging roll on the east side of the deposit. Some zones containing spodumene were cored, but they are either low in grade or altered and iron stained. INTRODUCTION A report on the Beecher No. 3 Black Diamond pegmatite, Ouster County, S. Dak., including a map and inferred cross sections, was published in 1959 (Redden, 1959). In the fall of 1960, the pegmatite was core-drilled by the Lithium Corp. of America under Office of Minerals Exploration contract 6,083. This core-drilling provided a partial test of the previously interpreted structure and the inferred distribution of beryl; it also supplied added detail on the subsurface character of the deposit. Six BX core holes, totaling 1,740.9 feet, were drilled in the deposit. One split of each core was logged by the writer (table 1), although the first part of the core from hole 2 was unfortunately ground to a minus 0.5 inch and the textures destroyed before it was examined. El E2 CONTRIBUTIONS TO ECONOMIC GEOLOGY Core recovery in pegmatite was generally good. The drill core of the country rock was not available for logging. These data permit the construction of new cross sections of the pegmatite, as shown in plate 1. The writer wishes to thank the Lithium Corp., of America and its representatives, especially J. N. McClure and F. F. Clarke, for permission to publish the results of this work and to examine chemical assays. DESCRIPTION OF PEGMATITE UNITS At the surface, the Beecher No. 3 Black Diamond pegmatite contains five distinguishable zones (Redden, 1959, p. 543-548). From the contact inward they are (1) quartz-muscovite-albite peg­ matite (border zone), (2) albite-quartz-muscovite pegmatite (wall zone). (3) quartz-albite-muscovite-perthite-beryl pegmatite, (4) perth- ite-quartz-albite pegmatite, and (5) perthite-quartz pegmatite. Accessory minerals include beryl, tourmaline, spodumene, and apatite. In general, the muscovite content decreases and perthite increases inward from the contact. Zone 3 is discontinuous, and zone 5 occurs only in the thickest parts of the pegmatite. Fracture fillings containing spodumene and quartz cut across all zones. Details of the mineral character and distribution of these zones, and the general geologic setting of the pegmatite, are included in the published account (Redden, 1959). All zones except zone 3 were cut by one or more of the drill holes (table 1). In addition, two new zones were noted. One of these, which apparently is the downward extension of zone 3 consists of quartz-albite-perthite-muscovite pegmatite; the other, which lies in the center of the pegmatite body consists of quartz-albite-perthite- spodumene pegmatite. The distribution of all zones, and their inferred relation to the surface exposures, are shown in the cross sections. Zone 1 (border zone) was recognized in cores from holes 1, 3, and 4. At the surface it occurs along most contacts between pegmatite and country rock, but it is absent at about half of the subsurface contacts. The zone is normally 0.1 to 0.2 foot thick, and because it is so narrow, it is combined with zone 2 in some of the logs (table 1). The chief minerals are quartz, muscovite, and albite. Zone 2 (wall zone), cut by all six drill holes, ranges in thickness from 1 to 7 feet. The mineral character is similar to that at the surface. The zone consists dominantly of albite and quartz, which occur in nearly equal amounts, and it also carries about 10 percent muscovite. In holes 4, 5, and 6, the wall zone (as well as parts of adjacent inner zones) has as much as 10 to 15 percent of arsenopyrite(?) in veinlets or disseminated throughout the core. TABLE 1. Diamond-drill logs, Black Diamond pegmatite [Tr, trace] Volume percent 0-50.0 _ . ____ . _ . Overburden and schist. No core. 50.0-245.1 _______ . 245.1-245.2.-- __ I 45 45 10 Grain size loss than 0.1 in. 245.2-252.0 - 2 30 Tr 62 8 Blue phosphate Grain size about 0.5 in. at 251 ft. QKO A-OR7 7 3a 40 5 50 5 Beryl. I- Muscovite is in 0.5-in. books except at 266 ft where books are larger Tourmaline... .. 267.7-279.0.. 4 OC 50 25 Tr Tr 0.8 in. grain size. o 279.0-295.0 4 40 7 50 3 Spodumene-- !zj O Tourmaline - Tr Some of albite is sugary textured. Log of other core split reports a ?S-in. crystal ol beryl at 290 ft. ^ 6 70 15 5 5 Spodumene- ...... I 5 Perthite is only slightly perthitic and could more aptly be called H 295.0-310.5- . Unidentified Tr microcline. Fresh and altered spodumene crystals as much as phosphate 2.4 in. long. Part of albite is sugary textured. I mineral. > 310.6-329.0. 4 35 7 55 3 Spodumene-. ..... 1 * a H3 329.0-331.6.. ........ 4 20 60 20 13 331.6-333.1~ 2 30 60 10 Fine grained. Thin border zone at end. Schist contact is at 25° N* to core. 333.1-387.0...... Micashist. Not logged. Hole end 387.0 ft. CO CO TABLE 1. Diamond-drill logs, Black Diamond pegmatite Continued Mode (percent) Interval (feet) Zone Other minerals Additional data Quartz Pert bite Albite Musco­ vite Hole 2 Volume percent 0-50.0 .............. 60.0-104.0 104.0-110.5.. 2 40 50 10 Tr covery. 110.5-127.0. 3a 40 5 50 5 Tr that in surface exposures of zone 4 in southeast part of pegmatite except core has more muscovite and less perthite. Core recovery, 50 percent. 127.0-128.0.. 3a 65 5 30 filling. 128.0-131.6 i FP(?) 60 30 10 131.6-150.0 3a 30 5 60 5 150.0-155.5.. ...... ..... 3a(?) 10 80 10 155.5-156.6. 2 30 65 5 156.6-157.7..... 2 25 70 5 161.0-162.0 FF(?) 50 30 20 162.0-190.0- 3a(?) 30 65 5 Spodumene... I - 173.7 and 173.9 ft. Small rounded grain of beryl between 183 and 186 ft where core recovery is only 50 percent. 190.0-196.0. 6(?) 50(?) 25(?) 25 a fracture filling. 196.0-216. 3a 25 65 8 1 Tr Fine grained. Gneissose structure in some of core. Core brecciated I 216.0-225.0.. _ 6(?) 40 25 10 15 Tr measuring 1.5 by 2 in. at 225 ft. Could be a series of spodumene- b earing fracture fillings. 225.0-234.0. _ .. ....... 3a(?) 40 20 40 234.0-236.6. 2 15 65 . 15 5 Schist contact is at 63° to core. 236.6-239.0.,-.. 239.0-240.1.. 2 Pegmatite. Same as 234-236.6 interval. No contact angles avail­ able. 240.1-241.1. 241.1-241.8- Pegmatite. Same as 234-236.6 interval. 241.8-255.0- Schist country rock. Hole ends 255.0 ft. Holed 0-104.6..... __ ........ 104.6-105.0..... _ ..... 1 65 35 Average grain size about 0.1 in. Schist contact is at 80° to core. 105.0-110.9 55 in 15 110. 9- 111.1....... ...... 1 40 40 20 cd 111.1-123.9 123.9-124.0 .......... 1 60 40 124.0-129.0......... 2 50 40 10 3 in. in diameter. 129.0-132.3 3a 40 40 20 132.3-141.1 5 15 80 5 141.1-142.6 i FF(?) 95(?) 5(?) co very. 142.6-186.9 5 10 85 5 Tr The hole was in the same crystal of perthite for at least 15 ft.
Load more

Recommended publications
  • Compilation of Reported Sapphire Occurrences in Montana
    Report of Investigation 23 Compilation of Reported Sapphire Occurrences in Montana Richard B. Berg 2015 Cover photo by Richard Berg. Sapphires (very pale green and colorless) concentrated by panning. The small red grains are garnets, commonly found with sapphires in western Montana, and the black sand is mainly magnetite. Compilation of Reported Sapphire Occurrences, RI 23 Compilation of Reported Sapphire Occurrences in Montana Richard B. Berg Montana Bureau of Mines and Geology MBMG Report of Investigation 23 2015 i Compilation of Reported Sapphire Occurrences, RI 23 TABLE OF CONTENTS Introduction ............................................................................................................................1 Descriptions of Occurrences ..................................................................................................7 Selected Bibliography of Articles on Montana Sapphires ................................................... 75 General Montana ............................................................................................................75 Yogo ................................................................................................................................ 75 Southwestern Montana Alluvial Deposits........................................................................ 76 Specifi cally Rock Creek sapphire district ........................................................................ 76 Specifi cally Dry Cottonwood Creek deposit and the Butte area ....................................
    [Show full text]
  • Not for Publication United States Court of Appeals
    NOT FOR PUBLICATION FILED DEC 20 2018 UNITED STATES COURT OF APPEALS MOLLY C. DWYER, CLERK FOR THE NINTH CIRCUIT U.S. COURT OF APPEALS CYNTHIA CARDARELLI PAINTER, No. 17-55901 individually and on behalf of other members of the general public similarly situated, D.C. No. 2:17-cv-02235-SVW-AJW Plaintiff-Appellant, v. MEMORANDUM* BLUE DIAMOND GROWERS, a California corporation and DOES, 1-100, inclusive, Defendants-Appellees. Appeal from the United States District Court for the Central District of California Stephen V. Wilson, District Judge, Presiding Argued and Submitted December 3, 2018 Pasadena, California Before: D.W. NELSON and WARDLAW, Circuit Judges, and PRATT,** District Judge. * This disposition is not appropriate for publication and is not precedent except as provided by Ninth Circuit Rule 36-3. ** The Honorable Robert W. Pratt, United States District Judge for the Southern District of Iowa, sitting by designation. Cynthia Painter appeals the district court’s order dismissing her complaint with prejudice on grounds of preemption and failure to state a claim pursuant to Federal Rule of Civil Procedure 12(b)(6). On behalf of a putative class, Painter claims that Blue Diamond Growers (“Blue Diamond”) mislabeled its almond beverages as “almond milk” when they should be labeled “imitation milk” because they substitute for and resemble dairy milk but are nutritionally inferior to it. See 21 C.F.R. § 101.3(e)(1). We have jurisdiction under 28 U.S.C. § 1291 and review the district court’s dismissal de novo. Durnford v. MusclePharm Corp., 907 F.3d 595, 601 (9th Cir.
    [Show full text]
  • In Montana's Gravel Bars; Diamond Once Found in Pioneer Gulch
    ' w .- CHOTBAU ÀCANTHA in Montana’s Gravel Bars; Diamond Once Found in Pioneer Gulch By IDWAIO B. REYNOLDS 1T is doubtful If even Ripley weald consider diamond mining in Mon- New $225,000 Residence Hall At State University Completed bat- such a venture is not Montana Dwarf Looks Back . entirely improbable. Mining in the ITreasure mate always baa been connected with tbe various mrtsH ■ On Life of Colorful Events principally gold, silver, copper, sine and lead. It is on these metals that With not more than three years left birthday he grew to his full height oí Butte has gained its reputation of be­ to live, Don Ward of Missoula, Mon­ 47 inches. As a trapeze performer his ing situated on "the richest hill on tana’s only native-son dwarf, is out toweight was 75 pounds. He now weighs earth,” and that Anaconda was created "make the most” of his remaining days,123 pounds. as the site of the world’s largest copper looking back on a colorful past packed Butte Favorite City smelter with Great Falls as the site with a multitude of interesting ex­ In recent years Ward has worked as of one of the world's greatest copper periences such as the average personan entertainer in various Montana refineries. is never privileged to enjoy. cities and appeared at several celebra­ However, despite all the fame gained Now 64, the 47-inch-tall man who tions. Butte is among his favorite cities. by these three cities in the mining was Mrs. Tom Thumb’s original coach­ “I’ve been three years in Europe and world for metals, Montana is also famed man in Europe, who traveled the circus 19 times in every state and every as a mining state in which precious routes for 19 years and who is the onlyprovince of Canada, but I’ve never met gems are found in commercially im­ little man ever to work on a trapeze,a better class of people, more con­ portant quantities.
    [Show full text]
  • Diamond Craters Oregon's Geologic
    Text by Ellen M. Benedict, 1985 Features at stops correspond to points on a clock ago, a huge mass of hot gases, volcanic ashes, bits face. Imagine that you are standing in the middle of a of pumice and other pyroclastics (fire-broken rock) Travel And Hiking Hints clock face. Twelve o’clock is the road in front of you violently erupted. The blast – greater than the May and 6 o’clock the road behind. If you always align the 18, 1980, eruption of Mt. St. Helens – deposited a Diamond Craters is located in the high desert country clock face with the road, you should be able to locate layer of pyroclastics 30 to 130 feet thick over an area about 55 miles southeast of Burns, Oregon. It’s an the features. almost 7,000 square miles! isolated place and some precautions should be taken . when traveling in the area. Start Tour. Mileage begins halfway Pyroclastics are between milepost 40 and 41 on State normal behavior Diamond Craters has no tourist facilities. The nearest Highway 205 at the junction to Diamond. for magmas place where gasoline is sold is at Frenchglen. Turn left. (subsurface That’s the opinion held by scores of molten rocks) Keep your scientists and educators who have visited Diamond, Oregon, a small ranching community, was of rhyolitic (a vehicle on named in 1874 for Mace McCoy’s Diamond brand. volcanic material and studied the area. It has the “best and hard-packed The nearby craters soon became known as Diamond related to granite) most diverse basaltic volcanic features in the road surfaces Craters.
    [Show full text]
  • JD: Jewelry Design
    JD: Jewelry Design JD 101 — Introduction to Jewelry JD 115 — Metal Forming Techniques: Fabrication Chasing and Repousse 2 credits; 1 lecture and 2 lab hours 1.5 credits; 3 lab hours Basic processes used in the design and Introduces students to jewelry-forming creation of jewelry. Students fabricate their techniques by making their own dapping own designs in the studio. and chasing tools by means of forging, JD 102 — Enameling Techniques for annealing, and tempering. Using these Precious Metals/Fine Jewelry/Objects tools, objects are created by repousse and D'Art other methods. 2 credits; 1 lecture and 2 lab hours Prerequisite(s): all first-semester Jewelry Vitreous enameling on precious metals. Design courses or approval of chairperson Studies include an emphasis on the "Co-requisite(s): JD 116, JD 122, JD metallurgical properties of gold, silver, and 134, JD 171, and JD 173 or approval of platinum and their chemical compatibility chairperson. with enamels. Surface treatments, ancient JD 117 — Enameling for Contemporary and modern, that intensify the jewel- Jewelry like qualities of vitreous enamel on 2 credits; 1 lecture and 2 lab hours precious metal will be explored. along with Vitreous enamel has been used for construction techniques that help students centuries as a means of adding color transform glass into beautiful, functional and richness to precious objects and jewelry and objects of art. jewelry. This course examines historical Prerequisite(s): JD 101. and contemporary uses of enamel, and JD 103 — Jewelry and Accessories explores the various methods of its Fabrication (Interdisciplinary) application, including cloisonne, limoges 2 credits; 1 lecture and 2 lab hours and champleve, the use of silver and gold This is an interdisciplinary course cross- foils, oxidation, surface finishing and setting listed with LD 103.
    [Show full text]
  • Kimberley Process Clean Diamond Trade Act Fact Sheet
    Kimberley Process Clean Diamond Trade Act The Kimberley Process Certification Scheme Export Requirements regulates the international rough diamond trade. The . Exports of rough diamonds from the United scheme is an internationally recognized certification States must be accompanied by a Kimberley system that establishes requirements to designate certificate, obtained from a U.S. Kimberley shipments of rough diamonds as conflict-free and prevent Process licensee and validated by the U.S. them from entering legitimate trade. Census Bureau. The Clean Diamond Trade Act was implemented on . Rough diamonds may only be exported to countries that participate in the Kimberley Process. July 29, 2003. The act requires that rough diamonds www.federalregister.gov imported or exported from the United States be controlled through the Kimberley Process. Exports of rough diamonds must be sealed in a tamper-resistant container. Packaging must have Importing requirements an indicator or barrier that can reasonably provide visible evidence that tampering had . Imports of rough diamonds must be accompanied occurred. by an original Kimberley Process certificate. U.S. Census Bureau requires that export information in filed through the automated export . Rough diamonds may be imported or exported system. Submitting export information through only to countries that participate in the Kimberley this system must be done in advance and Process. www.federalregister.gov confirmed by the return of an internal transaction Sheet number. Regardless of quantity or value, shipments must be entered on a formal entry. Importers may . Returning this number to the filer will validate the retain a customs broker at the relevant port of Kimberley certificate to export rough diamonds entry to assist with filing.
    [Show full text]
  • Gemstones by Donald W
    GEMSTONES By Donald W. olson Domestic survey data and tables were prepared by Nicholas A. Muniz, statistical assistant, and the world production table was prepared by Glenn J. Wallace, international data coordinator. In this report, the terms “gem” and “gemstone” mean any gemstones and on the cutting and polishing of large diamond mineral or organic material (such as amber, pearl, petrified wood, stones. Industry employment is estimated to range from 1,000 to and shell) used for personal adornment, display, or object of art ,500 workers (U.S. International Trade Commission, 1997, p. 1). because it possesses beauty, durability, and rarity. Of more than Most natural gemstone producers in the United states 4,000 mineral species, only about 100 possess all these attributes and are small businesses that are widely dispersed and operate are considered to be gemstones. Silicates other than quartz are the independently. the small producers probably have an average largest group of gemstones; oxides and quartz are the second largest of less than three employees, including those who only work (table 1). Gemstones are subdivided into diamond and colored part time. the number of gemstone mines operating from gemstones, which in this report designates all natural nondiamond year to year fluctuates because the uncertainty associated with gems. In addition, laboratory-created gemstones, cultured pearls, the discovery and marketing of gem-quality minerals makes and gemstone simulants are discussed but are treated separately it difficult to obtain financing for developing and sustaining from natural gemstones (table 2). Trade data in this report are economically viable deposits (U.S.
    [Show full text]
  • Garnets from the Camafuca-Camazambo Kimberlite (Angola)
    Anais da Academia Brasileira de Ciências (2006) 78(2): 309-315 (Annals of the Brazilian Academy of Sciences) ISSN 0001-3765 www.scielo.br/aabc Garnets from the Camafuca-Camazambo kimberlite (Angola) EUGÉNIO A. CORREIA and FERNANDO A.T.P. LAIGINHAS Departamento de Geologia, Faculdade de Ciências da Universidade do Porto Praça de Gomes Teixeira, 4050 Porto, Portugal Manuscript received on November 17, 2004; accepted for publication on June 13, 2005; presented by ALCIDES N. SIAL ABSTRACT This work presents a geochemical study of a set of garnets, selected by their colors, from the Camafuca- Camazambo kimberlite, located on northeast Angola. Mantle-derived garnets were classified according to the scheme proposed by Grütter et al. (2004) and belong to the G1, G4, G9 and G10 groups. Both sub-calcic (G10) and Ca-saturated (G9) garnets, typical, respectively, of harzburgites and lherzolites, were identified. The solubility limit of knorringite molecule in G10D garnets suggests they have crystallized at a minimum pressure of about 40 to 45 kbar (4– 4.5 GPa). The occurrence of diamond stability field garnets (G10D) is a clear indicator of the potential of this kimberlite for diamond. The chemistry of the garnets suggests that the source for the kimberlite was a lherzolite that has suffered a partial melting that formed basaltic magma, leaving a harzburgite as a residue. Key words: kimberlite, diamond, garnet, lherzolite, harzburgite. INTRODUCTION GEOCHEMICAL STUDY OF GARNETS The Camafuca-Camazambo kimberlite belongs to The geochemical study of mantle-derived garnets a kimberlite province comprising over a dozen of occurring in kimberlites progressed remarkably in primary occurrences of diamond, located along- recent years, as their chemistry is not only a possible side the homonymous brook which is a tributary of indicator of the presence of diamonds in their host the Chicapa river, in the proximity of the Calonda rock but also their abundance is a likely indicator of village, northeast Angola (Fig.
    [Show full text]
  • Olivine – Peridot 橄欖石 Prof
    Olivine – Peridot 橄欖石 Prof. Dr H.A. Hänni, FGA, SSEF Research Associate Email: [email protected] Fig. 1 Peridots rough and cut, from various locations. Photo © H.A.Hänni 作者述了寶石級橄欖石的特性，它歸屬於橄欖石 類礦物，它有三種成因，化學成的改變而引致顏 色、折射率和比重的變異，並簡報其內含物、人工 合成方法和產地，以及作為首飾時應注意的地方。 Peridot is a widely appreciated green gemstone (Fig. 1). It belongs to the Olivine group, which also includes the major minerals forsterite Mg2SiO4, fayalite Fe2SiO4 and tephroite Mn2SiO4. Olivines are the main constituents of maic and ultramaic rocks that are formed in the earth’s mantle. Olivine-basalt rocks bring the crystals to the surface, where they are found e.g. in extended basalt layers such as in China (Hebei province) (Fig. 2), and the Fig. 3 A Pallasite, an iron-nickel matrix with olivine crystals. Photo © H.A.Hänni USA (Arizona). Another genetic type of olivines is found in rocks formed by metamorphism like in Myanmar or Pakistan. Olivines are also the main constituents of rare pallasites, nickel-iron meteorites, with large inclusions of olivine (Fig. 3). Synthetic forsterites with dopants are used for laser technology applications. Gemstone olivine is called peridot, and also chrysolite. It is represented by a solid mixture between the Mg member forsterite (fo) and the Fe member fayalite (fa), with high fo and low fa concentrations. Occasional Fig. 2 An olivine-basalt rock sample with olivine grain contributions of Mn, Ni or Cr are always very small, but clusters and a larger olivine crystal from Zhangjikou- inluence the colour of the stone. Forsterite and fayalite Xuanhua, Hebei Province, China. are a solid solution series just as pyrope and almandine Photo © H.A.Hänni garnets.
    [Show full text]
  • Investing in Colored Diamonds from Diamond Investment Dealers
    BENEFITS OF INVESTING IN COLORED DIAMONDS FROM DIAMOND INVESTMENT DEALERS When investing in diamonds you need an ad- ly appreciated in value. Over the last decade, visor who has the depth and breadth of knowl- Argyle pink diamonds have consistently bro- edge in investment grade diamonds. Rare ken records on the global auction market, Diamond Investor provides seamless access demonstrating the robust nature of the dia- for savvy investors. We focus exclusively on mond market and the unceasing international natural fancy-colored diamonds and are staffed demand. Christies auctions have surpassed by experts in every facet of the diamond mar- records the last few years for both the most ket. This level of experience and expertise not expensive investment grade diamonds and only gives us greater understanding of the di- the highest price per carat. In April 2014, Chris- amond market, but also gives us access to a ties auctioned top quality, fancy pink, blue professional global network of investors, col- and yellow diamonds with prices exceeding of lectors and industry specialists including the $1 to $2 million per carat, leading Christies most sought after gemologists and diamond to declare 2014 the year of the colored dia- cutters in the world. mond. Rahul Kadakia, Head of Christies New York, states, At a time when other investments have suf- fered unparalleled chaos and uncertainty, “A colorless D-grade diamond at auction will make about $150,000 a carat, while a pink natural fancy-colored diamonds have steadi- fancy-colored diamond will make $1.5 million a carat, 10 times the price.” He also stated, “This is where the market is.
    [Show full text]
  • Two Treated-Color Synthetic Red Diamonds Seen in the Trade
    Two TREATED-COLORSYNTHETIC RED DIAMONDSSEEN IN THE TRADE By Thomas M.Moses, llene Reinitz, Emmanuel Fritsch, andJames E. Shigley - - -- -- -- Two dark brownish red faceted stones, recently submitted to the GIA Gem Trade Laboratory for standard origin-of-color reports, were found to be treat- ed synthetic diamonds. This conclusion was based on observations of: patterns of zoned color, U.V. luminescence, and graining; metallic inclu- sions; and certain bands in the visible- and infrared-range absorption spec- tra. We believe that this is one of the first published reports of treated-color synthetic diamonds seen asfaceted gems. For some of the gemological features desen3ed here, such as visible-grangespectra with sharp absorption bands, this is one of the first reported occurrences in gemquality synthetic diamonds. In early July 1993, a diamond dealer submitted a 0.55- gemological properties indicated that both had been ct dark brownish orangy red diamond (figure 1, left) to color enhanced subsequent to synthesis. the New York office of the GIA Gem Trade Laboratory To date, the GIA Gem Trade Laboratory has (GIA GTL) for a standard origin-of-color report. examined only a very few faceted synthetic diamonds According to the client, this round brilliant-cut stone that were submitted by members of the jewelry indus- had been obtained on memo from a dealer in Bombay, try for a laboratory report (see also the brief mention India. In September, a 0.43-ct dark brownish red "radi- of GIA GTL's examination of a 0.23-ct faceted ant1'-cut diamond (figure 1, right) was submitted in S~~rnitoinosynthetic yellow diamond in Fryer, 1987).
    [Show full text]
  • Novel Diamond/Sapphire Probes for Scanning Probe Microscopy Applications
    IOP Publishing Journal of Physics: Conference Series 61 (2007) 770–774 doi:10.1088/1742-6596/61/1/154 International Conference on Nanoscience and Technology (ICN&T 2006) Novel diamond/sapphire probes for scanning probe microscopy applications Bernard Mesa1 and Sergei Magonov2 1MicroStar Technologies, Huntsville, TX 77340, USA; 2Veeco Instruments, Santa Barbara CA 93117 USA E-mail: [email protected] Abstract. Novel diamond/sapphire probes are introduced for different scanning probe microscopy applications: from nanoindentation to high-resolution imaging of soft samples. These probes have sharp diamond tips with apex size below 10 nm and their stiffness/resonant frequency and tip shape can be adjusted for customer needs. Several examples of imaging with novel probes are given. Probes with conducting diamond tips exhibited high-sensitivity in electric force microscopy study. 1. Introduction In the development of scanning probe microscopy (SPM) the availability of sharp probes has been always one of the crucial factors. In the pioneering SPM method - scanning tunneling microscopy (STM), conducting probes, which are used for detection of tunneling current, are made either by electrochemical etching of metal wire or even by a more simple mechanical sharpening (e.g. cutting wire with scissors). Though the overall shape of the electrochemically- etched and mechanically sharpened probes is quite different, the probes of both kinds have been successfully applied for atomic-scale imaging of flat conducting and semiconducting surfaces of various inorganic and organic crystals. This is a consequence of the fact that only most advanced atoms of the probe are involved in electron transfer process between the probe apex and a sample.
    [Show full text]