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Opal from Nevada [POSTCARD]
Opal from Nevada POSTCARD

Price: $0.25

Product Code: PC016

Title: Opal from Nevada

Author: photo by J. Scovil
Year: 2005
Series: Postcard PC16
Format: postcard, 4 x 6 inches, full color

Opal from Nevada, 2.5 cm diameter, Virgin Valley district, Humboldt County. B. and F. Cureton collection. Photo by J. Scovil. Opal (SiO2 · nH2O) is the state gemstone of Nevada. Opal is generally considered to be amorphous (no definite crystaline structure) silica; however, partially crystaline varieties exist. The mineral is commonly deposited near or at the surface by thermal water. Opal in this sample occurs as petrified wood. For more information see Nevada Bureau of Mines and Geology Special Publication 31, Minerals of Nevada, for sale by NBMG.

Original Product Code: PC16