Agate
Image: <a href="//commons.wikimedia.org/wiki/User:Beckstet" title="User:Beckstet">Beckstet</a> (CC BY-SA 3.0)
Mineral NameAgate
Chemical FormulaSiO2
Mohs Hardness6.5
Crystal Systemamorphous
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.6
Colorsyellowish-white, brown, black
Transparencytranslucent
Type LocalityBrazil, Uruguay, Mexico, USA
Mineral GroupSilicates
Usesjewelry, ornamental objects, industrial, collector
Associated Mineralscalcite, zeolites, other forms of quartz
Raritycommon
Description
A translucent slice of agate, illuminated from behind, revealing intricate, wavy bands of dark brown to black against a lighter yellowish-white background.
Geological Context
Agate typically forms in cavities of volcanic rocks, such as basalt or rhyolite, where silica-rich fluids deposit successive layers of chalcedony, often with varying impurities that create its characteristic banding.
