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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
Gemstone. Group of precious and semiprecious stones—both uncut and faceted—including ( clockwise from top left) diamond, uncut synthetic sapphire, ruby, uncut emerald, and amethyst crystal cluster. A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, when cut or ...
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 ...
The first rank of gemstones, or precious stones, includes ruby, sapphire, diamond, and emerald. Orange topaz, also known as precious topaz, is the birthstone for the month of November, the symbol of friendship, and the state gemstone of the U.S. state of Utah. [24] Blue topaz is the state gemstone of the US state of Texas. [25]
Sapphire is one of the two gem-varieties of corundum, the other being ruby (defined as corundum in a shade of red). Although blue is the best-known sapphire color, it occurs in other colors, including gray and black, and also can be colorless. A pinkish orange variety of sapphire is called padparadscha .
A mixture of other minerals, often including pyrite. Lapis lazuli ( UK: / ˌlæpɪs ˈlæz ( j) ʊli, ˈlæʒʊ -, - ˌli /; US: / ˈlæz ( j) əli, ˈlæʒə -, - ˌli / ), or lapis for short, is a deep-blue metamorphic rock used as a semi-precious stone that has been prized since antiquity for its intense color.
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.
Emerald is a gemstone and a variety of the mineral beryl (Be 3 Al 2 (SiO 3) 6) colored green by trace amounts of chromium or sometimes vanadium. [ 2] Beryl has a hardness of 7.5–8 on the Mohs scale. [ 2] Most emeralds have many inclusions, [ 3] so their toughness (resistance to breakage) is classified as generally poor.