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| Contents 4 Map: Notable Opal Localities 50 BY BRUCE PAUL GABER 6 The Opal Enigma: Science, History...and Pins Afire: Play of Color in Opal BY MAX WEIBEL Sparkling Opal in Ancient Bones: Precious Relics...vibrant with opal pattern and color. In this extreme close-up of a Lightning Ridge black opal, the field...approximately 3 mm wide. Opal courtesy Jenni Brammall BY ALEX RITCHIE 52 An Opal Glossary of Terms BY...BY SI AND ANN FRAZIER BY PETER HUBER 64 Opal from Mexico: Unsurpassed Fire BY JURGEN SCHUTZ 18 Perfect |
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| 1982 Jules Roger Sauer ” Foreword For years Brazil has been the major producer of colored stones in...metamorphic rocks, the variety of gem deposits in Brazil is almost infinite. In addition to the mineral...assemblage one might expect from pegmatite dikes, Brazil also produces a very significant output of diamonds...written in English, and beautifully illustrated. “Brazil, Paradise of Gemstones’, by Jules Roger Sauer,...Grande do Norte, in 1953, the precious opals of Pedro I] in Piaui, in 1960, and a turquoise vein near |
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| d been detected in the spectrum, albeit weakly. Black octahedral inclusions, which williamsite has, plus...good density figure for nephrite. Nephrite too has black octahedra a n d weak chromium J. Gemm. 1976, XV...recently. A good distantvision reading indicated opal, but our customer didn't think it could be, such...nondestructive a n d the material, which was probably opal, was frangible to say the least. A matching density...comparison stone established the stone to be opal. * * * Another opal, which caused me a lot of trouble customerwise |
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| in Russia each weighing approximately 1 ct. Table II. The spectrum of the ordinary ray (o) is characterized...! 500 700 800 1 600 Wavelength (ran) Table II: UV/VIS absorption maxima and assignments Absorption...alkali ions and the weaker band is caused by type-II water molecules which are bound to alkali ions. ...inclusion patterns also typical of such emeralds, and black platelets (Figure 6) may well be hematite (cf. Schmetzer...with liquid and two-phase inclusions and hexagonal black platelets also form a typical inclusion pattern |
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| moving products from mine to consumer. The main cover image was taken at the AnahÌ mine in Bolivia, a major...of the company (Even-Zohar, 2007). Because of the mine closures, De Beers’s market share by volume fell...embarked on a plan to promote black businesses under a series of Black Economic Empowerment (BEE) initiatives...companies, including De Beers, to have a minimum of 26% black equity within five years. The diamond portion of...Still, the DTC for- Figure 4. A renewed desire for black empowerment and beneficiation took root in the southern |
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| TECHNIQUES 282 An Investigation of a Suite of Black Diamond Jewelry Robert C. Kammerling, Robert E....during its brief tenure in the USSR after World War II. In the authors' opinion, the consistency of these...Vaults before they were damaged during World War II. Photo 0 The Worshipful Company of Goldsmiths, London...a ribbon-like design set with rows of small old-mine-cut diamonds that sweeps up from the sides and culminates...(figure 91. THE COUNTRY OF ORIGIN DEBATE: INDIA OR BRAZIL? Tillander (1988) states that "without doubt the |
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| method on the apex of the cabochon with a Duplex II refractometer and white light source. Optic Character:...based on Philemon Holland's translation of 1601). II: "... [Median smaragdi] appear naturally of a green...green foil backings for pale stones and closed black settings for fissured stones. Equally astonishing...natural emeralds from two localities, the USSR and Brazil USSR (URALS): Single stone approx. 1ct £15 per...four stones approx. 1ct total weight £15 the set Brazil: Single heart-shaped approx. O.25ct £12 per stone |
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| opalescence the milky effect seen in common opal and in some precious opal. Not to be confused with play of colour...itself - olivine may be altered to serpentine and opal or agate may be deposited in cavities. Contact metamorphism...by hot mineral-bearing solutions which may allow opal and other gem materials to form. 1.1 FORMATION...the stone came from - sometimes down to the actual mine. Today it is commonplace to see in sale catalogues...Crystals of tourmaline are frequent in rock crystal; black tourmaline is usually of pegmatitic origin and green |
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| Onicolo Onyx 158 Sardonyx 202 Turquoise 224 Opal 159 Scapolite 202 Uvarovite 231 Orthoclase...minerals were densely con- centrated. This type of mine was very at- tractive, since it avoided the need...materials Quartz crystals from Corinto, Minas Gerais, Brazil. Height: 15 cm. Sorbonne collection using gravity...Washing diamond-bearing gravel in Minas Gerais, Brazil. Photo: tals of such minerals as quartz, fluorite...and a jeweler might then speak of a ‘root’ as Brazil Length: 9 cm. K. Proctor collection, United States |
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| opalescence the milky effect seen in common opal and in some precious opal. Not to be confused with play of colour...itself - olivine may be altered to serpentine and opal or agate may be deposited in cavities. Contact metamorphism...by hot mineral-bearing solutions which may allow opal and other gem materials to form. 1.1 FORMATION...stone came from — some¬ times down to the actual mine. Today it is commonplace to see in sale catalogues...Crystals of tourmaline are frequent in rock crystal; black tourmaline is usually of pegmatitic origin and green |
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| -~~1---------- 1960-2015 by Thom.as P. Moore Volume II I-Z Published by the Mineralogical Record, Inc....old dumps. In 1975-1976, Brunet collected sharp, black, flattened hexagonal ilmenite crystals to 7 .5 cm...Springfield show ( 1995: 582). Madawaska [Faraday] mine near Bow Lake, Hastings County. Some of the world's...property of, the old Madawaska uranium mine (called the Faraday mine before 1964). The mineral assemblage...with ilmenite being found as sharp, submetallic black, flattened rhombohedrons (resembling those of Froland |
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| considered as an area of scientific research of black and white smokers, rather than an area of exploration...Nontronite Nosean Nsutite Nyerereite Olivenite Olivine Opal Orpiment Otavite Paladium Paragonite Paralstonite...hanging wall. During a subsequent mining period, the mine was re-opened to recover sideritic parts of the...to an orthopyroxene bearing tonalite. A gray or black holocrystalline nepheline monzogabbro or nepheline...Aplite Argillite Arkose Basalt Bauxite Beforsite Black shale Blue schist Busorite Calcrete Calcsilicate |
| | Journal (article/letter/editorial) |
| considered as an area of scientific research of black and white smokers, rather than an area of exploration...Nontronite Nosean Nsutite Nyerereite Olivenite Olivine Opal Orpiment Otavite Paladium Paragonite Paralstonite...hanging wall. During a subsequent mining period, the mine was re-opened to recover sideritic parts of the...to an orthopyroxene bearing tonalite. A gray or black holocrystalline nepheline monzogabbro or nepheline...Aplite Argillite Arkose Basalt Bauxite Beforsite Black shale Blue schist Busorite Calcrete Calcsilicate |
