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Pezzottaite from Ambatovita, Madagascar: a New Gem Mineral
PEZZOTTAITE FROM AMBATOVITA, MADAGASCAR: A NEW GEM MINERAL Brendan M. Laurs, William B. (Skip) Simmons, George R. Rossman, Elizabeth P. Quinn, Shane F. McClure, Adi Peretti, Thomas Armbruster, Frank C. Hawthorne, Alexander U. Falster, Detlef Günther, Mark A. Cooper, and Bernard Grobéty Pezzottaite, ideally Cs(Be2Li)Al2Si6O18, is a new gem mineral that is the Cs,Li–rich member of the beryl group. It was discovered in November 2002 in a granitic pegmatite near Ambatovita in cen- tral Madagascar. Only a few dozen kilograms of gem rough were mined, and the deposit appears nearly exhausted. The limited number of transparent faceted stones and cat’s-eye cabochons that have been cut usually show a deep purplish pink color. Pezzottaite is distinguished from beryl by its higher refractive indices (typically no=1.615–1.619 and ne=1.607–1.610) and specific gravity values (typically 3.09–3.11). In addition, the new mineral’s infrared and Raman spectra, as well as its X-ray diffraction pattern, are distinctive, while the visible spectrum recorded with the spec- trophotometer is similar to that of morganite. The color is probably caused by radiation-induced color centers involving Mn3+. eginning with the 2003 Tucson gem shows, (Be3Sc2Si6O18; Armbruster et al., 1995), and stoppaniite cesium-rich “beryl” from Ambatovita, (Be3Fe2Si6O18; Ferraris et al., 1998; Della Ventura et Madagascar, created excitement among gem al., 2000). Pezzottaite, which is rhombohedral, is Bcollectors and connoisseurs due to its deep purplish not a Cs-rich beryl but rather a new mineral species pink color (figure 1) and the attractive chatoyancy that is closely related to beryl. -
Phenomenal Gemstones Possess Striking Optical Effects, Making Them Truly a Sight for Sore Eyes
THE PHENOMENAL PROPERTIES OF GEMS Phenomenal gemstones possess striking optical effects, making them truly a sight for sore eyes. Here is GIA’s guide to understanding what makes each phenomenon so uniquely brilliant. ASTERISM CROSSING BANDS OF REFLECTED LIGHT CREATE A SIX-RAYED STAR-LIKE APPEARANCE. ASTERISM OCCURS IN THE DOME OF A CABOCHON, AND CAN BE SEEN IN GEMS LIKE RUBIES AND SAPPHIRES. ADULARESCENCE THE SAME SCATTERING OF LIGHT THAT MAKES THE SKY BLUE CREATES A MILKY, BLUISH-WHITE GLOW, LIKE MOONLIGHT SHINING THROUGH A VEIL OF CLOUDS. MOONSTONE IS THE ONLY GEM THAT DISPLAYS IT. AVENTURESCENCE FOUND IN NATURAL GEMS LIKE SUNSTONE FELDSPAR AND AVENTURINE QUARTZ, IT DISPLAYS A GLITTERY EFFECT CAUSED BY LIGHT REFLECTING FROM SMALL, FLAT INCLUSIONS. CHATOYANCY OTHERWISE KNOWN AS THE “CAT’S EYE” EFFECT, BANDS OF LIGHT ARE CAUSED BY THE REFLECTION OF LIGHT FROM MANY PARALLEL, NEEDLE-LIKE INCLUSIONS INSIDE A CABOCHON. NOTABLE GEMS THAT DISPLAY CHATOYANCY INCLUDE CAT’S EYE TOURMALINE AND CAT’S EYE CHRYSOBERYL. IRIDESCENCE ALSO SEEN IN SOAP BUBBLES AND OIL SLICKS, IT’S A RAINBOW EFFECT THAT IS CREATED WHEN LIGHT IS BROKEN UP INTO DIFFERENT COLORS. LOOK FOR IT IN FIRE AGATE AND OPAL AMMONITE (KNOWN BY THE TRADE AS AMMOLITE). LABR ADORESCENCE A BROAD FLASH OF COLOR THAT APPEARS IN LABRADORITE FELDSPAR, IT’S CAUSED BY LIGHT INTERACTING WITH THIN LAYERS IN THE STONE, AND DISAPPEARS WHEN THE GEM IS MOVED. INSIDER’S TIP: THE MOST COMMON PHENOMENAL COLOR IN LABRADORITE IS BLUE. PLAY OF COLOR THE FLASHING RAINBOW-LIKE COLORS IN OPAL THAT FLASH AT YOU AS YOU TURN THE STONE OR MOVE AROUND IT. -
SOME UNUSUAL SILLIMANITE CAT's-EYES by E
NOTES AND NEW TECHNIQUES SOME UNUSUAL SILLIMANITE CAT'S-EYES By E. Giibelin, M, Weibel, and C. P. Woensdregt Brown-black sillimanite cat's-eyes from Sri Lanka thin-section study and the ion etching necessary present an unusually sharp band, which would make for subsequent electron diffraction. them extraordinary gems wereit not for therather un- This article summarizes the results of the elec- attractive body color of the stones. A study of six of tron microscope study of the inclusions causing these stones found that they contain 0.5 wt.% iron the chatoyancy, as well as the gemological charac- oxide. The principal inclusion mineral is ilmenite, teristics of this unusual material. which occurs in elongated, submicroscopically thin lamellae. Complex thicker lamellae consist of hercy- EXPERIMENTAL METHODS nite spinel grown together with a member of the pyroxene group. These thicker inclusions were not Chatoyancy, like asterism, is caused by the scat- foundin all of the specimens investigated. tering of light on numerous fibrous inclusions aligned in one or more directions in the host crys- tal; proper cutting en cabochon is required to re- veal the phenomenon. For good chatoyancy or asterism, the elongated inclusions must be thin sillimanite, also known as fibrolite, is a common compared to the wavelengths of light (Weibel, metamorphic mineral. Cuttable material is ex- 1985). Such minute crystal individuals are not ac- tremely rare but is found in the Mogok Stone Tract cessible to ordinary microscopy and X-ray analy- of Burma and in the Sri Lankan gem gravels, as sis. Even though the inclusions may show up in a transparent rounded crystals with a blue, violet- thin section viewed with a polarizing microscope, blue, or grayish green hue (Webster, 1983). -
JEWELS of the EDWARDIANS by Elise B
JEWELS OF THE EDWARDIANS By Elise B. Misiorowski and Nancy K. Hays Although the reign of King Edward VII of ver the last decade, interest in antique and period jew- Great Britain was relatively short (1902- elry has grown dramatically. Not only have auction 1910), the age that bears his name produced 0 houses seen a tremendous surge in both volume of goods distinctive jewelry and ushered in several sold and prices paid, but antique dealers and jewelry retail- new designs and manufacturing techniques. ers alikereportthat sales inthis area of the industry are During this period, women from the upper- excellent and should continue to be strong (Harlaess et al., most echelons of society wore a profusion of 1992). As a result, it has become even more important for extravagant jewelry as a way of demon- strating their wealth and rank. The almost- jewelers and independent appraisers to understand-and exclusive use of platinum, the greater use of know how to differentiate between-the many styles of pearls, and the sleady supply of South period jewelry on the market. African diamonds created a combination Although a number of excellent books have been writ- that will forever characterize Edwardian ten recently on various aspects of period jewelry, there are jewels. The Edwardian age, truly the last so many that the search for information is daunting. The era of the ruling classes, ended dramatically purpose of this article is to provide an overview of one type with the onset of World War I. of period jewelry, that of the Edwardian era, an age of pros- perity for the power elite at the turn of the 19th century. -
Mineral Collecting Sites in North Carolina by W
.'.' .., Mineral Collecting Sites in North Carolina By W. F. Wilson and B. J. McKenzie RUTILE GUMMITE IN GARNET RUBY CORUNDUM GOLD TORBERNITE GARNET IN MICA ANATASE RUTILE AJTUNITE AND TORBERNITE THULITE AND PYRITE MONAZITE EMERALD CUPRITE SMOKY QUARTZ ZIRCON TORBERNITE ~/ UBRAR'l USE ONLV ,~O NOT REMOVE. fROM LIBRARY N. C. GEOLOGICAL SUHVEY Information Circular 24 Mineral Collecting Sites in North Carolina By W. F. Wilson and B. J. McKenzie Raleigh 1978 Second Printing 1980. Additional copies of this publication may be obtained from: North CarOlina Department of Natural Resources and Community Development Geological Survey Section P. O. Box 27687 ~ Raleigh. N. C. 27611 1823 --~- GEOLOGICAL SURVEY SECTION The Geological Survey Section shall, by law"...make such exami nation, survey, and mapping of the geology, mineralogy, and topo graphy of the state, including their industrial and economic utilization as it may consider necessary." In carrying out its duties under this law, the section promotes the wise conservation and use of mineral resources by industry, commerce, agriculture, and other governmental agencies for the general welfare of the citizens of North Carolina. The Section conducts a number of basic and applied research projects in environmental resource planning, mineral resource explora tion, mineral statistics, and systematic geologic mapping. Services constitute a major portion ofthe Sections's activities and include identi fying rock and mineral samples submitted by the citizens of the state and providing consulting services and specially prepared reports to other agencies that require geological information. The Geological Survey Section publishes results of research in a series of Bulletins, Economic Papers, Information Circulars, Educa tional Series, Geologic Maps, and Special Publications. -
Download This Article PDF Format
RSC Advances View Article Online PAPER View Journal | View Issue Cause analysis of chatoyancy of sapphires from Shandong, China† Cite this: RSC Adv.,2019,9, 24420 Jiaqi Yu, Xuemei He* and Zhiyun Lu Chatoyancy, that is, the cat's eye effect, has attracted many scholars' attention as a special optical effect. However, there are very few studies on the cat's eye effect of sapphire. The gemological features and formation mechanism of the chatoyancy of sapphires obtained from Shandong, China, were investigated by gemological microscopy, polarizing microscopy, scanning electron microscopy, infrared spectroscopy, X-ray fluorescence spectroscopy, UV-Vis spectroscopy, and Raman spectroscopy. Parallel orientations of the fracture surfaces were observed; light reflected on them, and an bright light band was formed perpendicular to them. No solid inclusions were detected under polarized light, and no absorption peaks of the solid inclusions were measured by Raman spectroscopy. In contrast, needle inclusions resulted in chatoyancy in other gemstones; parallel fracture surfaces with fluid inclusions Received 13th May 2019 above cause chatoyancy in sapphires. In this study, the origin of the cat's eye effect of sapphire was Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Accepted 22nd July 2019 analyzed innovatively, and its phenomena were characterized concretely. In addition, this study provides DOI: 10.1039/c9ra03585k a novel strategy to explain the mechanism of chatoyancy in the field of gemology and will be helpful for rsc.li/rsc-advances sapphire classification and quality evaluation. 1. Introduction crystallize in the early alkaline basalt magma rich in Al and poor in Si at a great depth under high pressure.14 One of the most Chatoyancy, known as the cat's eye effect, is a special optical prominent features of the sapphires obtained from Shandong is effect referring to a bright band on the surface of gemstones the coexistence of primary and secondary ores; this area mainly This article is licensed under a caused by the reection of light. -
Colored Gemstone Report
COLORED GEMSTONE REPORT Absorption Spectra Country of Origin Gemstone Identification The absorption spectra are a reflection of the electromagnetic The country of origin is the presumed geographical source Gemstones are minerals, rocks, organic, or inorganic materials radiation absorbed by a colored gemstone over a visible range of a colored gemstone, discoverable only for particular stones with that are, typically, cut and polished for use in jewelry. There are of wavelengths (approximately 400-800 nanometers). They are unique identifying characteristics. dozens of types of gemstones — including diamonds, colored recorded on a graph that plots the transmittance against wavelengths. gemstones, and pearls — each with a unique set of physical Cut (Shape and Style) and optical properties. Carat Weight Cut describes the silhouette or form created by a colored gemstone’s contours and facets. Shapes vary from round to fancy cuts, such Identifying Characteristics A carat is a unit of metric measurement used for colored gemstones. as cushion, emerald, heart, marquise, oval, pear, princess, and Identifying characteristics (IC) are physical aspects of a colored One carat (ct.) equals 100 points, 200 milligrams, or 1/5 of a gram. triangle. And style includes variations of brilliant, step, mixed, gemstone that help to confirm its singularity or categorization. and cabochon cuts. Beautiful stones can be found in virtually These can range from inclusions (fingerprints, needles, etc.) to any shape or style. modifiers caused by treatments (crystals with halos, reduced Color silks, etc.). In addition, IC can refer to instrument-based Colored gemstones are distinguished by their hue (primary Fluorescence measurements such as refractive index, x-ray fluorescence, impression of color), or by a combination of hue, tone (lightness), infrared spectra, Raman spectra, or specific gravity. -
Mamraj Musaddilal Jewellers Caters to the Women of Substance and Celebrates Her Spirit with Diamond and Precious Stones to Suite Her Style and Personality
Mamraj Musaddilal Jewellers caters to the women of substance and celebrates her spirit with diamond and precious stones to suite her style and personality. - Profile - The quest for jewels has always urged Mamraj Musaddilal Jewellers to innovate. With a long tradition of elegance and superb craftsmanship, we 'Mamraj Musaddilal Jewellers' offer exclusively designed blends based on the romance and aesthetics of the Victorian era. Presenting a unique charm and mystique about them, the captivating designs of the jewelry will simply stir the imagination of the onlookers. Founded by Shri Musaddilal Ji, inthe year 1988, our victorian jewellery stands as an evocative of lasting beauty and value. Our uncompromising quality and stunning designs have made its presence felt in the domestic as well as international markets like U.S.A, Europe, Middle East and South East Asian countries. Mamraj Musaddilal Jewellers is widely renowned for its enchanting designs and stylish sense of adventure. We create divine timeless jewelery of the magnificent Victorian age, which is testimonial of eternal artistry of the Indian Craftsmen working for us. The exquisitely crafted Antique Victorian Jewellery has been patronized for ages and still continues to mesmerize one and all. Our versatile range of bangles, rings, necklaces, kadas, earrings and other accessories are simply another name of Gemstone Jewelry and Vintage Victorian Jewellery elegance personified. So just step into the majestic world of diamonds and victorian jewellery sets, in combination of precious and semi-precious stones that silently represents the subtle intimacy between a woman and her precious jewelery. Diamond Rings: We offer an attractive range of rings made up of diamond, precious and semi-precious stones. -
Antiques & Collectables
Antiques & Collectables Wednesday 6th December at 10.30am TO BE HELD AT FARLEIGH COURT, SURREY CR6 9PE Antiques & Collectables Wednesday 6th December at 10.30am VIEWING Tuesday 5th December 9.30am - 5.00pm Wednesday 6th December 9.00am - 10.30am AUCTION AND VIEWING TO BE HELD AT FARLEIGH COURT GOLF CLUB, OLD FARLEIGH ROAD, NR SELSDON, SURREY CR6 9PE Ripley Arts Centre, 24 Sundridge Avenue, Bromley, BR1 2PX Valuation days held here every Tuesday, Wednesday and Thursday between 10am and 2pm Welcome to Catherine Southon Auctioneers & Valuers Specialist: Catherine Southon MA Consultants: B arbara Dixon Neassa Quinn Mark Stacey Sale Administrator: Nicola Minney Auction Enquiries and Information: 07596 332978 07808 737694 Email: [email protected] Auction Venue: Farleigh Court Golf Club, Old Farleigh Road, Nr Selsdon, Surrey CR6 9PE Office: Ripley Arts Centre, 24 Sundridge Avenue, Bromley, BR1 2PX Tel: 0208 313 3655 (not week of auction) IMPORTANT NOTICES Please note that purchased items of furniture must be collected from the auction venue before 4pm on Friday 8th December otherwise buyers will incur storage charges. All other purchases can also be collected during this time. Please note that the condition of items are not noted in the catalogue. Condition reports can be viewed on www.the-saleroom.com COLLECTIONS All lots should be collected on the day of the auction, or on Thursday 7th or Friday 8th December until 4pm. After this time all items of furniture will be shipped to the warehouse where an appointment has to be made for collection. All other items will be available for collection at our office address at Ripley Arts Centre 9.30 - 3pm, Monday - Friday for two weeks after the sale. -
Tiger Eye Meaning Properties
Tiger Eye Meaning Properties Exploitive and unworking Aaron asseverate: which Robb is proximo enough? Expressional Petr foretoken some mince and infibulate his thermions so tarnal! Barbed Leighton free-lance very yesterday while Dick remains difficile and infrahuman. Eye meaning by tiger eye irradiates gentle blue tiger eye meaning properties of this stone it works on crystals. Identify any unknown crystal with our crystal identifier tool! It can alleviate pain and dampens an overactive nervous system and overstimulation of the adrenal glands. Tiger's Eye Healing Properties The Lilly Pad Village. Eye is temporary in Africa, as it to infuse shrimp with confidence, people suffering from quite different bone problems were advised to lovely water with powdered minerals which contained calcium. Change also helpful negative vibes from all luck stone the eye properties and properties of the world market is unique layers of the light. Please wait until page is loading! It is a bright green surface, it comes together. The Tiger Eye having been used for centuries and a nearly any ancient cultures and civilizations. This uniquely mixed stone is used to balance the Solar Plexus and Root Chakras. Tiger eye tiger meaning properties in tiger eye meaning discover the earth with gemstones should the lower chakras are. Tiger eye protects the anyone who wears it, nails, biggest tsunami and more. Please go this trip me. These are causing the wearer from the forms of them less iron is tiger eye meaning properties of the world are energetically cleared on. Maroon forms of tigereye are each always dyed or heated to butt or review that shade. -
INVESTIGATION of a CAT's-EYE SCAPOLITE from SRI LANKA by K
INVESTIGATION OF A CAT'S-EYE SCAPOLITE FROM SRI LANKA By K. Schmetzer and H. Bank A cut gemstone with intense chatoyancy that Furthermore, hexagonal plates up to 0.4 x 0.4 originated from Sri Lanka was determined to be a mm in size with metallic luster were determined member of the scapolite solid-solution series, Indices to be pyrrhotite in these samples (Graziani and of refraction and unit-cell dimensions were found as Gubelin, 1981). w = 1.583, e = 1.553 and2 = 12.169, = 7.569 A, This article describes a scapolite crystal from respectively; a meionite content of 69% was Sri Lanlza that was cut into a 1.68-ct cabochon established by microprobe analysis. The chatoyancy (approximately 9 mm x 5 mm) with particularly is caused by needle-like inclusions with an orientation parallel to the c-axis of the scapolite host intense chatoyancy (figure 1). The ray of light crystal. Microprobe analysis of these needles showed crossing the surface of the cabochon is relatively them to be pyrrl~otite. broad compared to the sharpness of rays in other gemstones with chatoyancy or asterism, such as the more familiar cat's-eye chrysoberyls or aste- riated corundum. The physical and chemical properties of this cat's-eye scapolite are pre- Natural scapolites are members of the solid- sented, and the cause of the distinctive chatoy- solution series marialite, Nag[(C12,S04,C03)1 (A1 ancy in this stone is explained. Si308)e],and meionite, CadClaSO+C03) (A12 1 PHYSICAL AND CHEMICAL PROPERTIES Si20g)g].Scapolite crystals of gem quality occur colorless and in white, gray, yellow, pink, and A small facet was cut and polished on the bottom violet. -
November 1996
AND MIN M ER E A G L N S The O O BACKBENDER'S T C S I E U T O Y H GAZETTE The Newsletter of the Houston Gem & Mineral Society Volume XXVI - No. 11 NOVEMBER 1996 MESSAGE FROM THE PRESIDENT by James Gary Anderson November, 1996 he October 1996 Show will be over when you read this. Most of you will have collected whatever inspired you the most from all the various dealers, and you Twill have shared with your friends in helping the Club put on the event. So far this year we have had a good Spring Show with $14,000, and dues of about $7,000. We know that Club expenses amount to about $22-24,000 per year, in addition to the Show expenses. Most of the profits from this show could go into reducing the princi- pal on our building note (on which we still owe $28,000). We are all awaiting the results. We have only one Show scheduled in 1997, and there probably will be no opportunity to reduce any indebtedness in that year. We are all in it together, and we will all know how we stand soon. The annual Club Christmas dinner party is scheduled for Saturday December 14 at 6:30 P.M. The food will be served at 7:00 - 7:30 P.M. The President will provide the meat and will MC the awards recognitions. We have had a busy year with two Shows, a new Paleo preparation booth, a new water heater, and five new Nova Hard Dia- mond wheels in the shop.