ENHANCED LAPIDARY MATERIALS FANCY COMPRESSED BLOCKS: the LATEST TREND Helen Serras-Herman FGA

Total Page:16

File Type:pdf, Size:1020Kb

ENHANCED LAPIDARY MATERIALS FANCY COMPRESSED BLOCKS: the LATEST TREND Helen Serras-Herman FGA FEATURE ARTICLE ENHANCED LAPIDARY MATERIALS FANCY COMPRESSED BLOCKS: THE LATEST TREND Helen Serras-Herman FGA We all love using natural untreated gem materials for our lapidary projects and jewelry artwork. We like the organic feel, the symphony of colors, the diversity of textures, the quality and the uniqueness, grateful to Mother Nature for creating all these beautiful rarities. esides the fact that some of the all-natural materials have become very limited or completely unobtainable Bfrom the mine sources, while others are getting harder to find uncut on the market or their prices have risen dramat - ically as is the case with turquoise, sugilite, gaspeite and ocean jasper, a new trend in lapidary materials has entered the market: natural enhanced lapidary materials . The traditional way of enhancing gemstones has been by dying or resin-stabilization in order to simulate a more ex - pensive and rare version of the same material, or to make soft and fragile materials harder so that they can survive the lapidary processes of cutting and polishing. Today, many of the natural gem materials have been color enhanced to look like some other natural material, and the results are “simulants” or “look-a-likes.” Although they are imitating another material, they are not “imitations” as are glass and FIGURE 1. Blocks by Colbaugh Processing. plastics, because they are of natural origin. Another en - hancement that we have seen in recent years in drusy gemstones, besides dying, has been coating with metals, sequently for less final cost, except for the desired thickness such as gold, platinum or titanium. and pattern. The slab is then easily shaped into geometric or free-form cabochons. But the most recent breed of enhanced lapidary materials comes in the form of fancy compressed blocks, comprised There are two main problems surrounding these stones. One of natural gemstone ingredients, metals, shells and resins, is the lack of disclosure. Although the original wholesaler some in stunning colors and unimaginable mineral combina - dealers or lapidaries may have disclosed information about tions never seen before. They are compressed with resin the nature of the rough, cabochons or beads, somewhere under heat and pressure and are durable to be used into jew - down the line, or especially with online sales of second and elry. Many of these enhanced gem materials are very attrac - third parties, information gets lost or blurred. The second tive with bold and eye-catching patterns, striking colors and problem is that appraisers are not familiar with these prod - unique designs—our natural world with a face lift! ucts, and consider all of them as “junk,” placing them in the same category as glass or plastic imitations. They should un - Coupled with a lower price point, which makes them an ap - derstand the origin of these materials, their properties and pealing alternative to the all-natural expensive gemstones, their current market value. these gemstones cut from fancy compressed blocks have become an instant hit among lapidaries and jewelry design - One of the reasons for disclosure, besides honesty, is for the ers. Figure 1. A great advantage the compressed blocks pro - lapidary, designer, metalsmith, or the final client or collector vide is that there is very little waste when slabbing them; to know how to take care of the jewelry set with these types even-sized slabs are easy to cut, compared to natural pieces of finished stones. How well will the stones wear once set that are irregular in shape, with inclusions, cracks and flaws into jewelry, especially into rings which take more abuse, or that the lapidary has to take into account and work around would they be best set in pendants and brooches? Will they them. There is no need for any special orientation of the endure a cleaning in an ultrasonic machine, the torch of the rough block material, which accounts for less labor and sub - jeweler, or a swim in the pool? GEMGUIDE - 1 - SEPTEMBER / OCTOBER 2017 LAPIDARY MATERIALS FIGURE 2. Natural Kingman turquoise compressed. FIGURE 3. Natural turquoise, infused with bronze. While many dealers of high-end gemstones and literature within the gemological world are focused on disclosure of enhancements of expensive faceted rubies, emeralds or di - amonds, the cabochon and bead market almost slides qui - etly under the disclosure radar. It is a huge market that affects a large percentage of sales in the commercial jewelry art and craft world. According to the Federal Trade Commission (FTC) Guides for the jewelry industry, with the exception of normal fashioning (cutting and polishing) it is the seller’s responsibility at all lev - els of commerce to clearly disclose to the buyer at the time of the sale whether the stone is natural or not. The seller must also provide all pertinent information about any en - hancement process when A) the treatment is not permanent FIGURE 4. Turquoise infused with bronze, finished. and its effects are lost over time, B) the treatment creates special care requirements for the gemstone to retain the ben - efits of the treatment, and C) the treatment has a significant effect on the value of the gemstone. My research for these types of gemstones started back in 2014 while I was looking at the booth of Keith Horst of A & K A great source of information is the Gemstone Information Gems and Minerals at a gem show in Arizona. Keith is a mas - Manual, 12 th edition, published by the American Gem Trade ter lapidary and teaches lapidary at the Yavapai College in Organization (AGTA), available to all on the Disclosure page Prescott, Arizona. He is recognized in the trade for his stun - at http://www.agta.org/info/index.html. There are sixteen ning cabochons, drusy cabs and unique natural surface ‘Gemstone Enhancement Codes’ supported by AGTA, and freeforms. I have great admiration for his work especially his when selling any gemstone, bead, or jewelry, one of these masterfully cut matched pairs for earrings. Looking through codes must be applied. Keith’s inventory many bizarre gemstones drew my attention. We started pairing the simulant pieces with natural gem - A vast majority of cabochons on the market today are treated stones, and a “natural vs. enhanced” story began to develop. with the fracture filler Opticon™, or polished with wax during After that initial encounter, I began looking for and finding the final step, facts rarely disclosed. Although I understand more “look-a-like” gem materials at other booths. that no dealer wants to put a sign in their booth stating that their stones are all treated, lapidaries and jewelry artists There are two main groups for these fancy compressed should let their customers know about their stones’ treat - blocks. One type comprises of small, natural nuggets of qual - ments and advise them of how to take care and protect the ity turquoise from Kingman, Arizona, which are compressed finished products. with resin into blocks, yet the outline of each nugget is still GEMGUIDE - 2 - SEPTEMBER / OCTOBER 2017 LAPIDARY MATERIALS visible. These compressed turquoise blocks (Figure 2) are cre - ated by Colbaugh Processing, Inc. (http://www.colbaugh.net/), a very-well known company that mines the only active mine for turquoise in Arizona: the Mineral Park Mine at Turquoise Mountain a few miles north of Kingman. The company is headed by Marty Colbaugh, the grandson of the original mine owner, S.A. “Chuck” Colbaugh, who first mined turquoise there in 1962. I had the opportunity to talk with Marty at his booth in Tucson, and he openly discussed the treatments used in his materi - als. I am very thankful to him for being very open in dis - cussing and disclosing all treatments. He was very emphatic that the all-natural turquoise blocks start with high-grade turquoise nuggets, and do not contain any dyes. Besides the all-natural turquoise blocks, he also creates com - pressed blocks of natural turquoise nuggets infused with bronze (Figure 3 and 4) or zinc that offer a very unique look FIGURE 6. Mohave green turquoise blocks. with tendrils of bright shiny metal, simulating natural turquoise with golden matrix inclusions from the Kingman mine or the Hachita mine in New Mexico. Figure 5. These have become extremely popular for use as cabochons and knife handles. The latest trend that Colbaugh Processing offers is a variety of dyed turquoise blocks, with or without infused bronze (for gold color) or zinc (for silver color), which are imitating another natural gem material. All blocks purchased directly from Col - baugh Processing weigh approximately 2.20 lbs and are cur - rently sold for $80 per pound. One variety called Mohave green turquoise (Figure 6) is a bright green dyed turquoise infused with zinc, simulating the rare bright green gaspeite [(Ni, Mg, Fe) CO 3] from Australia. Figure 7. FIGURE 7. Natural gaspeite. Gaspeite’s electric lime green to neon apple green color is due to its nickel con - tent. Slabs of natural untreated gaspeite are rarely available, and today may range in the $2 to $3 per gram at retail shows, while the Mohave green turquoise may sell for only $0.50 per gram. Most gaspeite cabs and beads are treated. Besides the blocks, it is offered di - rectly by Colbaugh Processing as bead FIGURE 5. Turquoise Sky, Hachita mine. FIGURE 8. Turquoise with abalone cabs. GEMGUIDE - 3 - SEPTEMBER / OCTOBER 2017 LAPIDARY MATERIALS FIGURE 11. Man-made dino bone cabs. FIGURE 9. Natural dino bone block. pany in Gilbert, Arizona, is known for selling natural and man- made gem material crushed into powder or into small chips that customers use for inlay projects in wood or pottery (http://stores.ebay.com/nichebox-rocks).
Recommended publications
  • Download Course Outline for This Program
    Program Outline 434- Jewellery and Metalwork NUNAVUT INUIT LANGUAGES AND CULTURES Jewelry and Metalwork (and all fine arts) PROGRAM REPORT 434 Jewellery and Metalwork Start Term: No Specified End Date End Term: No Specified End Date Program Status: Approved Action Type: N/A Change Type: N/A Discontinued: No Latest Version: Yes Printed: 03/30/2015 1 Program Outline 434- Jewellery and Metalwork Program Details 434 - Jewellery and Metalwork Start Term: No Specified End Date End Term: No Specified End Date Program Details Code 434 Title Jewellery and Metalwork Start Term No Specified End Date End Term No Specified End Date Total Credits Institution Nunavut Faculty Inuit Languages and Cultures Department Jewelry and Metalwork (and all fine arts) General Information Eligible for RPL No Description The Program in Jewellery and Metalwork will enable students to develop their knowledge and skills of jewellery and metalwork production in a professional studio atmosphere. To this end the program stresses high standards of craftship and creativity, all the time encouraging and exposing students to a wide range of materials, techniques and concepts. This program is designed to allow the individual student to specialize in an area of study of particular interest. There is an emphasis on creative thinking and problem-solving throughout the program.The first year of the program provides an environment for the students to acquire the necessary skills that will enable them to translate their ideas into two and three dimensional jewellery and metalwork. This first year includes courses in: Drawing and Design, Inuit Art and Jewellery History, Lapidary and also Business and Communications.
    [Show full text]
  • Lapidary Journal Jewelry Artist March 2012
    INDEX TO VOLUME 65 Lapidary Journal Jewelry Artist April 2011-March 2012 INDEX BY FEATURE/ Signature Techniques Part 1 Resin Earrings and Pendant, PROJECT/DEPARTMENT of 2, 20, 09/10-11 30, 08-11 Signature Techniques Part 2 Sagenite Intarsia Pendant, 50, With title, page number, of 2, 18, 11-11 04-11 month, and year published Special Event Sales, 22, 08-11 Silver Clay and Wire Ring, 58, When to Saw Your Rough, 74, 03-12 FEATURE ARTICLES Smokin’*, 43, 09/10-11 01/02-12 Argentium® Tips, 50, 03-12 Spinwheel, 20, 08-11 Arizona Opal, 22, 01/02-12 PROJECTS/DEMOS/FACET Stacking Ring Trio, 74, Basic Files, 36, 11-11 05/06-11 DESIGNS Brachiopod Agate, 26, 04-11 Sterling Safety Pin, 22, 12-11 Alabaster Bowls, 54, 07-11 Create Your Best Workspace, Swirl Step Cut Revisited, 72, Amethyst Crystal Cross, 34, 28, 11-11 01/02-12 Cut Together, 66, 01/02-12 12-11 Tabbed Fossil Coral Pendant, Deciphering Chinese Writing Copper and Silver Clay 50, 01/02-12 Linked Bracelet, 48, 07-11 12, 07-11 Stone, 78, 01/02-12 Torch Fired Enamel Medallion Site of Your Own, A, 12, 03-12 Easier Torchwork, 43, 11-11 Copper Wire Cuff with Silver Necklace, 33, 09/10-11 Elizabeth Taylor’s Legendary Wire “Inlay,” 28, 07-11 Trillion Diamonds Barion, 44, SMOKIN’ STONES Jewels, 58, 12-11 Coquina Pendant, 44, 05/06-11 Alabaster, 52, 07-11 Ethiopian Opal, 28, 01/02-12 01/02-12 Turquoise and Pierced Silver Ametrine, 44, 09/10-11 Find the Right Findings, 46, Corrugated Copper Pendant, Bead Bracelet – Plus!, 44, Coquina, 42, 01/02-12 09/10-11 24, 05/06-11 04-11 Fossilized Ivory, 24, 04-11
    [Show full text]
  • Rockhounds Herald
    The official bulletin of the Dothan Gem & Mineral Club, Inc. Rockhounds Herald 920 Yorktown Road, Dothan, AL 36301-4372 www.wiregrassrockhounds.com April 2012 Words from… The President No meeting this month since our gem and mineral show is scheduled for Saturday and Sunday, April 21 – 22. A lot of online calendars and other media sources have picked up the show announcement so we are expecting a really big turnout this year. Try to come at least one day, if you can…and bring your family and friends! If you are supplying door prizes for the show and have not yet given them to John Webber, please bring them directly to the show. Thanks. JoAn Announcements Jewelry Workshop – JoAn Lambert will be hosting a Frangipani Caterpillar Bracelet workshop at 1:00 PM on Saturday, April 28 at the fellowship hall. She will be bringing the printed patterns, but you’ll need to bring your own supplies. The following list of supplies will make one 7 ½ bracelet: 60 4mm faceted beads Size 12 beading needle Size 11 seed beads Size D beading thread or silamide Size 14 seed beads or charlottes Scissors ½” clasp bead or button Beeswax or Thread Heaven Note: If you’d like a longer bracelet, you’ll need to buy extra 4mm beads. The seed beads can be the same color as the 4mm beads or you can use gold or silver. Upcoming Shows April 21 – 22 Dothan Gem & Mineral Show Dothan, AL April 28 – 29 Memphis Mineral, Fossil, Jewelry Show Memphis, TN May 11 – 13 Georgia Mineral Society Show Marietta, GA Source: www.amfed.org/sfms/ Meeting3380688 Minutes – March 2012 – by Secretary The meeting was called to order by club President, JoAn Lambert, at 2:03 PM.
    [Show full text]
  • Symposium on Agate and Cryptocrystalline Quartz
    Symposium on Agate and Cryptocrystalline Quartz September 10 – 13, 2005 Golden, Colorado Sponsored by Friends of Mineralogy, Colorado Chapter; Colorado School of Mines Geology Museum; and U.S. Geological Survey 2 Cover Photos {top left} Fortification agate, Hinsdale County, Colorado, collection of the Geology Museum, Colorado School of Mines. Coloration of alternating concentric bands is due to infiltration of Fe with groundwater into the porous chalcedony layers, leaving the impermeable chalcedony bands uncolored (white): ground water was introduced via the symmetric fractures, evidenced by darker brown hues along the orthogonal lines. Specimen about 4 inches across; photo Dan Kile. {lower left} Photomicrograph showing, in crossed-polarized light, a rhyolite thunder egg shell (lower left) a fibrous phase of silica, opal-CTLS (appearing as a layer of tan fibers bordering the rhyolite cavity wall), and spherulitic and radiating fibrous forms of chalcedony. Field of view approximately 4.8 mm high; photo Dan Kile. {center right} Photomicrograph of the same field of view, but with a 1 λ (first-order red) waveplate inserted to illustrate the length-fast nature of the chalcedony (yellow-orange) and the length-slow character of the opal CTLS (blue). Field of view about 4.8 mm high; photo Dan Kile. Copyright of articles and photographs is retained by authors and Friends of Mineralogy, Colorado Chapter; reproduction by electronic or other means without permission is prohibited 3 Symposium on Agate and Cryptocrystalline Quartz Program and Abstracts September 10 – 13, 2005 Editors Daniel Kile Thomas Michalski Peter Modreski Held at Green Center, Colorado School of Mines Golden, Colorado Sponsored by Friends of Mineralogy, Colorado Chapter Colorado School of Mines Geology Museum U.S.
    [Show full text]
  • 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]
  • Get Reactive in System 96!
    Get Reactive in System 96! Uroboros has created two unique glass formulas for System 96 that are designed to create an interface color, or a reac on, when melted against certain other colors. This occurs when ions from the two adjacent glasses migrate and mingle when the gl asses become hot and ß uid. Given the right glass chemistry, the comingled ions form a very thin colored line, or reac on. Since our formulas react to create a no ceably reddish hue we named them Red Reac ves: as in Red Reac ve Transparent, and Red Reac ve Opal. The primary ingredient needed in a glass to generate a reac on color with our Reac ve glass is Copper. Copper is present in many blue and blue-green glass colors, but in some cases in too low a concentra on to create a no ceable reac on. For simplicity, all System 96 colors have been graded for their poten al to react into three categories: Strong, Medium, and Mild. See them all listed in the chart on the back of this page. You will Þ nd that the intensity of the reac on color will get stronger with longer, ho er, or repeat Þ rings. This is because the copper ions have more me to mingle with their friendly reac ve partners in the adjacent glass. The chart rankings are based on a typical single Þ ring cycle. You could get a Medium reac on from a color graded as Mild by Þ ring it ho er, or Þ ring mul ple mes.
    [Show full text]
  • Neycraft Centrifugal Casting Machine to Be Free from Defects in Material and Workmanship for a Period of Two Years from the Date of Sale
    CRUCIBLE SLIDE LEVER COUNTER BALANCE WEIGHT SILICA CRUCIBLE WINDING & LOCKING WARRANTY INVESTMENT FLASK KNOB FLASK RECEIVER WARRANTY: Except with respect to those components parts and uses which are described herein, ASSEMBLY DENTSPLY Neytech warrants the Neycraft Centrifugal Casting Machine to be free from defects in material and workmanship for a period of two years from the date of sale. DENTSPLY Neytech’s liability under this warranty is limited solely to repairing or, at DENTSPLY Neytech’s option, replacing those products included within the warranty which are returned to DENTSPLY Neytech within the applicable warranty period (with shipping charges prepaid), and which are determined by DENTSPLY Neytech to be defective. This warranty shall not apply to any product which has been subject to misuse; negligence; or accident; or misapplied; or modified; or repaired by unauthorized persons; or improperly installed. INSPECTION: Buyer shall inspect the product upon receipt. The buyer shall notify DENTSPLY Neytech in writing of any claims of defects in material and workmanship within thirty days after the buyer discovers or should have discovered the facts upon which such a claim is based. Failure of the SAFETY SHELL buyer to give written notice of such a claim within this time period shall be deemed to be a waiver of such claim. MOUNTING BASE DISCLAIMER: The provisions stated herein represent DENTSPLY Neytech’s sole obligation and exclude all other remedies or warranties, expressed or implied, including those related to MERCHANTABILITY and FITNESS FOR A PARTICULAR PURPOSE. LIMITATION OF LIABILITY: Under no circumstances shall DENTSPLY Neytech be liable to the buyer for any incidental, consequential or special damages, losses or expenses.
    [Show full text]
  • Malachite Cu2(CO3)(OH)2 C 2001-2005 Mineral Data Publishing, Version 1
    Malachite Cu2(CO3)(OH)2 c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Monoclinic. Point Group: 2/m. Crystals are acicular to prismatic, thick tabular, equant, with {100}, {010}, {001}, {110}, {201}, several other forms, rounded, in sprays and crude composite aggregates, to 9 cm; typically stalactitic, mammillary, botryoidal, as such, radially fibrous internally. Twinning: On {100}, {201}, very common as contact or penetration twins, also polysynthetic. Physical Properties: Cleavage: Perfect on {201}; fair on {010}. Fracture: Subconchoidal to uneven. Hardness = 3.5–4 D(meas.) = 4.05(2) D(calc.) = 3.983 Optical Properties: Translucent to opaque. Color: Bright green, dark green, blackish green, commonly banded in masses; green to yellowish green in transmitted light. Streak: Pale green. Luster: Adamantine to vitreous; silky if fibrous; dull to earthy if massive. Optical Class: Biaxial (–). Pleochroism: X = nearly colorless; Y = yellowish green; Z = deep green. Orientation: Y = b; X ∧ c = 23.5◦. Dispersion: r<v,moderately strong. α = 1.655(3) β = 1.875(3) γ = 1.909(3) 2V(meas.) = 43(2)◦ ◦ 0 Cell Data: Space Group: P 21/a. a = 9.502 b = 11.974 c = 3.240 β =98 45 Z=4 X-ray Powder Pattern: Synthetic. 2.857 (100), 3.693 (85), 5.055 (75), 5.993 (55), 2.520 (55), 2.778 (45), 2.464 (35) Chemistry: (1) (2) CO2 20.04 19.90 CuO 72.03 71.95 H2O 8.09 8.15 Total 100.16 100.00 (1) Rio Marina, Elba, Italy. (2) Cu2(CO3)(OH)2. Occurrence: A common secondary mineral formed in the oxidation zone of copper deposits; locally may be an ore of copper.
    [Show full text]
  • METAL ENAMELING Leader Guide Pub
    Arts & Communication METAL ENAMELING Leader Guide Pub. No. CIR009 WISCONSIN 4-H PUBLICATION HEAD HEART HANDS HEALTH Contents Before Each Meeting: Checklist ..............................1 Adhesive Agents or Binders ....................................6 Facilities Tools, Materials and Equipment Safety Precautions..................................................6 Resource Materials Kiln Firing and Table-Top Units Expenses Metal Cutting and Cleaning Planning Application of Enamel Colors Youth Leaders Other Cautions Project Meeting: Checklist ......................................3 Metal Art and Jewery Terms ...................................7 Purposes of 4-H Arts and Crafts ...........................................8 Components of Good Metal Enameling Futher Leader Training Sources of Supplies How to Start Working Prepare a Project Plan Bibiography ............................................................8 Evaluation of Projects Kiln Prearation and Maintenance ...........................6 WISCONSIN 4-H Pub. No. CIR009, Pg. Welcome! Be sure all youth are familiar with 4H158, Metal Enameling As a leader in the 4-H Metal Enameling Project, you only Member Guide. The guide suggests some tools (soldering need an interest in young people and metal enameling to be irons and propane torches), materials and methods which are successful. more appropriate for older youth and more suitable for larger facilities (school art room or spacious county center), rather To get started, contact your county University of Wisconsin- than your kitchen or basement. Rearrange these recommen- Extension office for the 4-H leadership booklets 4H350, dations to best suit the ages and abilities of your group’s Getting Started in 4-H Leadership, and 4H500, I’m a 4-H membership and your own comfort level as helper. Project Leader. Now What Do I Do? (also available on the Wisconsin 4-H Web Site at http://www.uwex.edu/ces/4h/ As in any art project, a generous supply of tools and pubs/index.html).
    [Show full text]
  • Piece Mold, Lost Wax & Composite Casting Techniques of The
    Piece Mold, Lost Wax & Composite Casting Techniques of the Chinese Bronze Age Behzad Bavarian and Lisa Reiner Dept. of MSEM College of Engineering and Computer Science September 2006 Table of Contents Abstract Approximate timeline 1 Introduction 2 Bronze Transition from Clay 4 Elemental Analysis of Bronze Alloys 4 Melting Temperature 7 Casting Methods 8 Casting Molds 14 Casting Flaws 21 Lost Wax Method 25 Sanxingdui 28 Environmental Effects on Surface Appearance 32 Conclusion 35 References 36 China can claim a history rich in over 5,000 years of artistic, philosophical and political advancement. As well, it is birthplace to one of the world's oldest and most complex civilizations. By 1100 BC, a high level of artistic and technical skill in bronze casting had been achieved by the Chinese. Bronze artifacts initially were copies of clay objects, but soon evolved into shapes invoking bronze material characteristics. Essentially, the bronze alloys represented in the copper-tin-lead ternary diagram are not easily hot or cold worked and are difficult to shape by hammering, the most common techniques used by the ancient Europeans and Middle Easterners. This did not deter the Chinese, however, for they had demonstrated technical proficiency with hard, thin walled ceramics by the end of the Neolithic period and were able to use these skills to develop a most unusual casting method called the piece mold process. Advances in ceramic technology played an influential role in the progress of Chinese bronze casting where the piece mold process was more of a technological extension than a distinct innovation. Certainly, the long and specialized experience in handling clay was required to form the delicate inscriptions, to properly fit the molds together and to prevent them from cracking during the pour.
    [Show full text]
  • On Palaeozoic–Mesozoic Brittle Normal Faults Along the SW Barents Sea Margin: Fault Processes and Implications for Basement Permeability and Margin Evolution
    research-articleResearch ArticleXXX10.1144/jgs2014-018K. Indrevær et al.Brittle Faults on the SW Barents Sea Margin 2014 Downloaded from http://jgs.lyellcollection.org/ by guest on October 9, 2021 Journal of the Geological Society, London. http://dx.doi.org/10.1144/jgs2014-018 Published Online First © 2014 The Authors On Palaeozoic–Mesozoic brittle normal faults along the SW Barents Sea margin: fault processes and implications for basement permeability and margin evolution KJETIL INDREVÆR1,2*, HOLGER STUNITZ1 & STEFFEN G. BERGH1 1Department of Geology, University of Tromsø, N-9037 Tromsø, Norway 2DONG E&P Norge AS, Roald Amundsens Plass 1, N-9257 Tromsø, Norway *Corresponding author (e-mail: [email protected]) Abstract: Palaeozoic–Mesozoic brittle normal faults onshore along the SW Barents Sea passive margin off northern Norway give valuable insight into fault and fluid flow processes from the lower brittle crust. Micro- structural evidence suggests that Late Permian–Early Triassic faulting took place during multiple phases, with initial fault movement at minimum P–T conditions of c. 300 °C and c. 240 MPa (c. 10 km depth), followed by later fault movement at minimum P–T conditions of c. 275 °C and c. 220 MPa (c. 8.5 km depth). The study shows that pore pressures locally reached lithostatic levels (240 MPa) during faulting and that faulting came to a halt during early (deep) stages of rifting along the margin. Fault permeability has been controlled by heal- ing and precipitation processes through time, which have sealed off the core zone and eventually the damage zones after faulting. A minimum average exhumation rate of c.
    [Show full text]
  • A Survey of the Gemstone Resources of China
    A SURVEY OF THE GEMSTONE RESOURCES OF CHINA By Peter C. Keller and Wang Fuquan The People's Republic of China has recently hina has historically been a land of great mystery, placed a high priority on identifying and C with natural resources and cultural treasures that, developing its gemstone resources. Initial until recently, were almost entirely hidden from the out- exploration by teams of geologists side world. From the point of view of the geologist and throughout China has identified many gemologist, one could only look at known geological maps deposits with significant potential, of this huge country and speculate on the potential impact including amher, cinnabar, garnets, blue sapphires, and diamonds. Small amounts of China would have on the world's gem markets if its gem ruby have' qlso been found. Major deposits resources were ever developed to their full potential. of nephriteyade as well as large numbers of During the past few years, the government of the Peo- gem-bearing pegmatite dilces have been ple's Republic of China (P.R.C.)has opened its doors to the identified.Significant deposits of peridot outside world in a quest for information and a desire for are crirrently being exploited from Hebei scientific and cultural cooperation. It was in this spirit of Province. Lastly, turqrloise rivaling the cooperation that a week-long series of lectures on gem- finest Persian material has been found in stones and their origins was presented by the senior author large quantities in Hubei and Shaanxi and a colleague to over 100 geologists from all over China Provinces.
    [Show full text]