Opal

A Peruvian opal (also called blue opal) is a semi-opaque to opaque blue-green stone found in Peru, which is often cut to include the matrix in the more opaque stones. It does not display a play of color. Blue opal also comes from [[Oregon]] and Idaho in the [[Owyhee River|Owyhee]] region, as well as from [[Nevada]] around the [[Virgin Valley]].<ref>{{Cite web|title=Opal – Nevada Mining Association|url=https://www.nevadamining.org/nvma_minerals/opal/|access-date=2020-06-18|website=www.nevadamining.org|date=19 December 2017 }}</ref>

A Peruvian opal (also called blue opal) is a semi-opaque to opaque blue-green stone found in Peru, which is often cut to include the matrix in the more opaque stones. It does not display a play of color. Blue opal also comes from [[Oregon]] and Idaho in the [[Owyhee River|Owyhee]] region, as well as from [[Nevada]] around the [[Virgin Valley]].<ref>{{Cite web|title=Opal – Nevada Mining Association|url=https://www.nevadamining.org/nvma_minerals/opal/|access-date=2020-06-18|website=www.nevadamining.org|date=19 December 2017 }}</ref>

Opal is also formed by [[diatom]]s. Diatoms are a form of algae that, when they die, often form layers at the bottoms of lakes, bays, or oceans. Their cell walls are made up of hydrated silicon dioxide which gives them [[structural coloration]] and therefore the appearance of tiny opals when viewed under a microscope. These cell walls or "tests" form the “grains” for the [[diatomaceous earth]]. This sedimentary rock is white, opaque, and chalky in texture.<ref>{{Cite web|url=http://www.minerals.net/mineral-variety/mineral/diatomite.aspx|title=diatomite – The Mineral and Gemstone Kingdom|website=www.minerals.net|access-date=2018-05-15}}</ref> Diatomite has multiple industrial uses such as filtering or adsorbing since it has a fine particle size and very porous nature, and gardening to increase water absorption.

Opal is also formed by [[diatom]]s. Diatoms are a form of algae that, when they die, often form layers at the bottoms of lakes, bays, or oceans. Their cell walls are made up of hydrated silicon dioxide which gives them [[structural coloration]] and therefore the appearance of tiny opals when viewed under a microscope. These cell walls or "tests" form the "grains" for the [[diatomaceous earth]]. This sedimentary rock is white, opaque, and chalky in texture.<ref>{{Cite web|url=http://www.minerals.net/mineral-variety/mineral/diatomite.aspx|title=diatomite – The Mineral and Gemstone Kingdom|website=www.minerals.net|access-date=2018-05-15}}</ref> Diatomite has multiple industrial uses such as filtering or adsorbing since it has a fine particle size and very porous nature, and gardening to increase water absorption.

==History==

==History==