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In 1986, California named benitoite as its state gemstone, a form of the mineral barium titanium silicate that is unique to the Golden State and only found in gem quality in San Benito County. [ 80 ] ^ Colorado is the only state whose geological symbols reflect the national flag's colors: red (rhodochrosite), white (yule marble), and blue ...
Commons. Diamond[ a] is a gemstone formed by cutting a raw diamond. Diamonds are one of the best-known and most sought-after gems, and they have been used as decorative items since ancient times. The hardness of diamond and its high dispersion of light —giving the diamond its characteristic "fire"—make it useful for industrial applications ...
Cut (gems) A decorative glass crystal about 4 cm (1.6 in) in diameter, having a facet cut often applied for gemstones. At some positions, coloured light (see rainbow colouring) can be regarded caused by the intended optical prism effect of the cut. A gemstone desired to be used in jewelry is cut depending on the size and shape of the rough ...
The carat (ct) is a unit of mass equal to 200 mg (0.00705 oz; 0.00643 ozt), which is used for measuring gemstones and pearls. The current definition, sometimes known as the metric carat , was adopted in 1907 at the Fourth General Conference on Weights and Measures , [ 1 ] [ 2 ] and soon afterwards in many countries around the world.
Gemstones of the World revised 5th edition, 2013 by Walter Schumann ISBN 978-1454909538 Smithsonian Handbook: Gemstones by Cally Hall, 2nd ed. 2002 ISBN 978-0789489852 v
Logan Sapphire. Star of Bombay, given to Mary Pickford by Douglas Fairbanks, Sr. Star of India. Stuart Sapphire. Black Star of Queensland. Star of Adam, with a weight of 1,404.49 carats (280.898 g), it is the largest star sapphire in the world. Queen Marie of Romania Sapphire.
New York City. , New York. , United States. Website. www .gemscience .net. Gemological Science International, or GSI, is an independent gemological organization that is one of the largest gemological entities in the world, with offices in four continents. [1] [2] [3]
The Gemological Institute of America ( GIA) is a nonprofit institute based in Carlsbad, California. It is dedicated to research and education in the field of gemology and the jewelry arts. [ 1] Founded in 1931, GIA's mission is to protect buyers and sellers of gemstones by setting and maintaining the standards used to evaluate gemstone quality.