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Sunday, September 07, 2008

Scheelite

Natural scheelite is often found in greyish white, yellow or brown colors + well-formed crystals are sought by collectors and occasionally fashioned into gemstones when free of flaws + under ultraviolet light the gem material fluoresces strong blue/the presence of molybdenum may produce a green glow.

Scheelite has been synthesized by the Czochralski/flux/vapor processes to imitate diamond, or as a scintillator/solid state lasing medium + synthetic scheelites are produced in many colors with rare earth dopants including purple, red brown, light green, yellow, yellow brown, deep red, dark yellow green, and colorless (pure) + natural scheelite can be identified from synthetic material by microscope (Natural =internal growth features/inclusions; Synthetic = clean or curved striae + clouds of minute gas bubbles) + spectroscope = absorption spectrum (rare earth =praseodymium and neodymium).

Collectors often confuse between natural and synthetic scheelites + end up paying high prices thinking they were buying genuine stones. If in doubt, always consult a reputed gem testing laboratory.

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