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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 hide
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 characteristic a gemologist uses to identify a gemstone is its chemical composition. For example, diamonds are made of carbon (C) and rubies of aluminium oxide (Al 2 O 3). Many gems are crystals which are classified by their crystal system such as cubic or trigonal or monoclinic.
Jasper breaks with a smooth surface and is used for ornamentation or as a gemstone. It can be highly polished and is used for items such as vases, seals, and snuff boxes. The density of jasper is typically 2.5 to 2.9 g/cm 3. [4] Jaspillite is a banded-iron-formation rock that often has distinctive bands of jasper.
Mineral tests are simple physical and chemical methods of testing samples, which can help to identify the mineral type. [1] This approach is used widely in mineralogy, ore geology and general geological mapping. [2]
A selection of ornamental, non-precious stones made by tumbling rough pebbles with abrasive grit in a rotating drum. The biggest pebble here is 40 millimetres (1.6 in) long. Gem identification is basically a process of elimination. Gemstones of similar color undergo non-destructive optical testing until there is only one possible identity.
Mineral symbols (text abbreviations) are used to abbreviate mineral groups, subgroups, and species, just as lettered symbols are used for the chemical elements.. The first set of commonly used mineral symbols was published in 1983 and covered the common rock-forming minerals using 192 two- or three-lettered symbols. [1]
Celestine (the IMA-accepted name) [6] or celestite [1] [7] [a] is a mineral consisting of strontium sulfate (Sr S O 4).The mineral is named for its occasional delicate blue color. ...