 | | Journal (article/letter/editorial) | | 99, pages 1488–1499, 2014 Australian sedimentary opal-A and its associated minerals: Implications for...precious opal on the world market comes from opal fields in the Great Artesian Basin of Australia pointing...analyzed 20 opal-A samples from the Andamooka (South Australia) and Yowah (Queensland) precious opal fields...silica, the mineral assemblage, and the host rock. Opal-A consists of submicrometer-sized silica spheres...dominant late-stage mineralization leading to precious opal happened at acidic pH. Our findings indicate that |  | | Journal (article/letter/editorial) | | lithologies of the Great Artesian Basin (central Australia). Our multi-method approach, using optical and...reveals that particle morphologies trace the flow of opal-forming colloidal suspensions and document syn-...clastic sediments. Keywords: silica; opal-A; common opal; precious opal; silica colloid; photonic crystal;...interface-coupled dissolution-precipitation; Australia 1. Introduction The hydrated mineralogical assemblages...assemblages of the Great Artesian Basin (central Australia) record the acidic oxidative weathering of volcaniclastic |  | | Journal (article/letter/editorial) | | THE GEM VARIETIES OF OPAL By RALPH C. GOSSE Albany, New York Introduction This paper is by no means...the many varieties, occurrences, colors, of the opal. Those only of gem quality will be treated here...groups, precious and common. Precious Opal: Any variety of the opal showing a play of color, regardless..."precious" used in connection with opal does not necessarily infer value, an opal may be of the precious variety...not gem quality, and vice versa. Common Opal: Any variety of opal which has no play of color, regardless |  | | Journal (issue) | | zircon, peridot, green tourmaline, Burma blue or white spinel. $1.00 ea. or 4 for $3.00 18" Sterling Silver...Willy Petersen-Fagerstam 52 A YANK IN THE OPAL FIELDS by J. Edward Warwict NEWS .._ THE GEM MINERALS...here with the Mule Mountains on the East, running South to the Palo Verde Mountains. The western boundary...and evaporates. From the Palo Verde Mountains, South and West, are numerous volcanic flows, chiefly basalt...we set up our camp and prepare to collect in the fields all around us. Several years ago this area was |  | | Book | | specifics of SiO2 modifications and varieties (e.g., opal, chalcedony, agate, quartz, amethyst). Following...seifertite, high-pressure silica glass, moganite or opal, are relatively rare in extraterrestrial materials...measurements; see Table S3). The analytical error ranges within 10% of the absolute concentration of the...behavior of trace elements in granitic quartz from South Norway. Contrib. Mineral. Petrol. 2004, 147, 615–628...geological materials, and is used in numerous industrial fields as a raw material. Mineralogy and the processing |  | | Book | | specifics of SiO2 modifications and varieties (e.g., opal, chalcedony, agate, quartz, amethyst). Following...seifertite, high-pressure silica glass, moganite or opal, are relatively rare in extraterrestrial materials...measurements; see Table S3). The analytical error ranges within 10% of the absolute concentration of the...behavior of trace elements in granitic quartz from South Norway. Contrib. Mineral. Petrol. 2004, 147, 615–628...geological materials, and is used in numerous industrial fields as a raw material. Mineralogy and the processing |  | | Journal (issue) | | F.G.A. North-West Branch: M. P. Gayton, F.G.A. South Yorkshire & District Branch: 1. R. M. Lewis, F.G...Colombo, Sri Lanka, in search of a type of milky white corundum that has become known as 'Geuda stone'...The stone and cell are held a few inches above a white paper so that the splotchiness of colour caused...inclusions encompassing two very conspicuous clusters of white crystals (Figure 8) (part of which protruded beyond...microprobe scrutiny, yielding the ensuing results: the white cluster consisted of the elements Na, AI, and Si |  | | Journal (issue) | | company—Archon Exploration Pty Ltd, in Perth, Western Australia—and a director of KWG Resources, Montreal, Canada...he has worked on projects in Australia, Brazil, Canada, India, and South Africa. He has a B.Sc. in geology...used in the exploration for diamond deposits in Australia, Africa, and, most recently, Canada combined...estimates of seismic-wave velocity for different depth ranges. Areas of increasingly high velocity (and probably...part of the continent (Canadian Shield). The depth ranges of maps a and b are shown on the right of the diagram |  | | Journal (issue) | | per lb. NEW! Plume Opal Is another new discovery in Mexico! This beautiful plume opal is hand-selected...sensitive and must be cut w ith special care as any opal. Our price is only . . . $1 .00 per oz. NEW! Turquol...cabochons with striking contrast between the lacy white bands and the black irregular stripes. Our low price... Colors are mostly gold, tan, flesh color. and white or clear agate mixed. It is an excellent value for... . .... . ... . . . .... . . . . Sl .25 per lb. Opal. Mttlco. blaclc plu11es In sal11on color epal . |  | | Journal (issue) | | .......................................... 65 SOUTH CENTRAL FEDERATION OF MINERAL SOCIETIES Olllcln...orange may contain an occasional streak of gray or white. It takes a good polish and may be cut for cabochons...$2.20 lb. RED AND WHITE STRIPED JASPER - Strong alternating bands of red and white makes this an Interesting...$2.00 per lb. TIGERIRON -Just received from Australia, a beautiful golden ttgereye banded In hematltell...polish and comes In combinations of red, pink, tan, white and cream colors. We have had many favorable responses |  | | Journal (issue) | | Treasurer 705 John Adams Pkwy., Idaho Falls, 10 83401 SOUTH CENTRAL FEDERATION OF MINERAL SOCIETIES Officers...orange may contain an occasional streak of gray or white. It takes a good polish and may be cut for cabochons...$2.20 lb. RED AND WHITE STRIPED JASPER - Strong alternating bands of red and white makes this an Interesting...$2.00 per lb. TIGERIRON -Just received from Australia, a beautiful golden tigereye banded In hematltel...Jasper from Australia. Takes an excellent polish and comes in combinations of red, pink, tan, white and cream |  | | Book | | OPER MRA IRAAD ESpease tet ec Oe ire ee Use SOUTH SNA c a ig ...Fossils..........ceccesssessscessesesseeees 191 Deep South Rivers—Fossilized Sharks Teeth and Fossils .......possible we have tried to include that / DIAMOND / OPAL MINING: ¢ Plastic Spray Bottle ¢ 1/8-, 1/4- and...Talc Gypsum, Pearl Calcite, Malachite Fluorite, Opal Apatite, Glass, Lapis Orthoclase, Jade, Hematite...by-product of lead mining. Gold was also discovered in South Carolina in the early 1800s. Lancaster County was |
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