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gem treatment

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Journal Article
Published: 01 January 2019
The Canadian Mineralogist (2019) 57 (1): 65-79.
... from 11 mining areas, focusing on the causes of the spectral differences, with a preliminary discussion of major controlling factors. The emerald samples were supplied by the sample library of Gems and Jade, Shanghai, China. They were collected by a member of the project group directly from 11...
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Journal Article
Journal: Elements
Published: 01 March 2005
Elements (2005) 1 (2): 101-104.
...James E. Shigley Abstract Annealing of gem-quality diamonds at very high pressures (above 5 GPa) and temperatures (above ∼1800°C) can produce significant changes in their color. Treatment under these high-pressure-high-temperature (HPHT) conditions affects certain optically active defects...
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Series: Geological Society, London, Special Publications
Published: 01 January 2013
DOI: 10.1144/SP375.9
EISBN: 9781862396432
...) Thus, the gem electuary seems to have been a relevant treatment from pre-natal care in pregnant women, through the various stages of life right into old age. While the authorship of the recipe is the subject of some debate, the electuary itself enjoyed great popularity both as an individual confection...
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Journal Article
Published: 01 July 2003
European Journal of Mineralogy (2003) 15 (4): 701-706.
...Stefanie SCHOTT; Helmut RAGER; Kay SCHÜRMANN; Michail TARAN Abstract Natural topaz crystals of gem quality and orange-red colour from the Ouro Preto area, Brazil have been analysed chemically and investigated by optical absorption and electron paramagnetic resonance measurements to elucidate...
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Journal Article
Published: 01 February 1947
American Mineralogist (1947) 32 (1-2): 31-43.
... disappear slowly upon exposure to light, and some revert without other stimulation. The anticipated availability of this treatment to temporarily improve commercial gems makes it important that jewelers be informed of the possibility so that they may be on their guard against frauds of this nature...
Series: European Mineralogical Union Notes in Mineralogy
Published: 01 January 2012
DOI: 10.1180/EMU-notes.12.13
EISBN: 9780903056366
... hints regarding heat-treatment: e.g . if diaspore is present in a corundum ( e.g . in fluid inclusions, as a daughter crystal; Fig. 1 ), as it decomposes below 1000°C in corundum, it is an indication that the gem has not been heat-treated at the usual treatment temperatures, well above 1500°C. However...
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Journal Article
Published: 01 January 2009
European Journal of Mineralogy (2009) 21 (1): 43-50.
...-temperature – high-pressure treatments . Proc. R. Soc. Lond. A ., 361 , 109 – 127 . Buerki , P.R. , Reinitz , I.M. , Muhlmeister , S. , Elen , S. ( 1999 ): Observation of the H2 defect in gem-quality type Ia diamond . Diamond Rel. Mat ., 8 , 1061 – 1066 . Collins , A.T...
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Journal Article
Published: 01 December 2017
American Mineralogist (2017) 102 (12): 2521-2522.
... cooling. While confirming that Ti dissolves into gem corundum and precipitates as rutile needles to obtain star sapphire, and that both processes are common practice in the heat treatment of ruby and sapphire at high temperatures (1800–1100 °C; e.g., Schmetzer et al. 2015 ), Palke and Breeding (2017...
Journal Article
Journal: Elements
Published: 01 June 2015
Elements (2015) 11 (3): 195-200.
..., through fluorescent lights, and through environmental remediation of contaminated soils. Apatite is truly a technological gem. Teeth (dentin and enamel) and bones are composed of apatite ( F ig . 2 ). Biologically precipitated apatite (nanocrystalline bioapatite) is structurally very similar to hydroxyl...
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Journal Article
Published: 01 July 2017
American Mineralogist (2017) 102 (7): 1451-1461.
... in the basal plane of the first-order prism with oriented needles in both cases intersecting themselves at an angle of 60°/120° ( Hughes 1997 ). Except for star rubies and sapphires, such inclusions, in general, are considered to detract from the gem's value. However, the advent of heat treatment of sapphires...
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Journal Article
Published: 01 August 2017
American Mineralogist (2017) 102 (8): 1747-1758.
.... Color is used not only to identify minerals but also to identify potential treatments to gems, chemical signatures, and sometimes to unravel a mineral's geological history. However, as we have shown here, in many cases, the color observed in a mineral or gem is a complicated interplay between not only...
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Journal Article
Published: 01 December 2006
Mineralogical Magazine (2006) 70 (6): 669-687.
... mining and secondary treatment ventures ( Coldham, 2003 ). The origins of these gem corundums from deep-seated sources, formed prior to basaltic transport, have had considerable debate, based on their gemmological characteristics, trace element geochemistry, mineral inclusions, isotopes...
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Journal Article
Published: 01 November 2008
American Mineralogist (2008) 93 (11-12): 1865-1873.
.... 2e ) and Honduras (Fig. 2e ). These opals are white, chalky, and extremely porous, and would be considered gems only after color treatment. Opal-AG samples from Australia, Brazil, France, Madagascar, Mexico, and the U.S.A. always contain some cement. Our study indicates that common opal-AG...
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Journal Article
Published: 01 May 2001
Geochemistry: Exploration, Environment, Analysis (2001) 1 (2): 157-162.
... by a method using infrared absorption . Bulletin of the Geological Survey of Finland 62 , 149 – 156 . SEARS , S. K. 1993 . Effects of Sample Treatment on Mixed-layer Illite-Smectite in X-ray Diffractograms and Transmission Electron Micrographs . MSc Thesis. McGill University , Montreal...
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Journal Article
Published: 01 August 2005
The Canadian Mineralogist (2005) 43 (4): 1205-1224.
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Journal Article
Published: 01 May 2005
Geochemistry: Exploration, Environment, Analysis (2005) 5 (2): 107-113.
... to the same ‘mortar and pestle’ treatment used in the preparation of the controls. These samples were then analysed by XRD (Bruker D8 Advance diffractometer with Co Kα radiation) using suspensions of these materials in water which were pipetted onto glass slides and air-dried. Using JADE TM software...
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Journal Article
Published: 01 February 2004
Geochemistry: Exploration, Environment, Analysis (2004) 4 (1): 7-32.
... extractant for carbonate, but little, if any, carbonate is inferred to have remained after the previous treatment, since the amounts of Ca extracted are low. This leach extracts more Zn that AA7 and the anomaly/background for AA5 is greater than for AA7. The next leach, cold hydroxylamine (HX Mn), extracts...
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Journal Article
Published: 01 May 2003
Geochemistry: Exploration, Environment, Analysis (2003) 3 (2): 107-120.
Journal Article
Published: 19 October 2016
Seismological Research Letters (2016) 87 (6): 1240-1253.
... emphasize the need for collaboration to make effective use of the knowledge collected by the various national organizations. Recognizing these challenges, the Global Earthquake Model ( GEM ) initiative since 2009 has invested resources to promote and support activities and projects aimed at stimulating...
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Journal Article
Published: 01 August 2003
Mineralogical Magazine (2003) 67 (4): 717-732.
... staining, which lends an orange tint to the grain. Some represent crystallographically orientated primary two-phase (liquid + gas) inclusions and, more rarely, three-phase (liquid + gas + daughter crystal) inclusions. Heat treatment of the ruby improves the consistency of the colour largely by eliminating...
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