Agate
Image: Hannes Grobe (CC BY-SA 2.5)
Mineral NameAgate
Chemical FormulaSiO2
Mohs Hardness6.5
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.6
Colorsorange, yellow, blue, grey
Transparencytranslucent
Type LocalityWorldwide (e.g., Brazil, Uruguay, Mexico, USA)
Mineral GroupSilicates
Usesjewelry, ornamental objects, industrial, collector
Associated Mineralsquartz, amethyst, calcite, zeolites
Raritycommon
Description
The image shows a polished section of agate, featuring distinct bands of orange and yellow surrounding a central cavity filled with bluish-grey microcrystalline quartz, possibly with some druzy crystals.
Geological Context
Agate forms primarily in volcanic rocks, where silica-rich fluids deposit layers of chalcedony within cavities or vesicles, often creating concentric bands. It can also be found in sedimentary rocks.
