Agate
Image: Вадим Кондратьев (CC BY-SA 3.0)
Mineral NameAgate
Chemical FormulaSiO2
Mohs Hardness6.5
Crystal Systemamorphous
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.6
Colorswhite, gray, blue, brown, red, pink, yellow, green, black, banded
Transparencytranslucent
Type LocalityWorldwide, often associated with volcanic regions
Mineral GroupSilicates
Usesjewelry, ornamental objects, carvings, collector
Associated Mineralsquartz, calcite, zeolites
Raritycommon
Description
Agate is a cryptocrystalline variety of silica, chiefly chalcedony, characterized by its fine grain and often vibrant, concentric banding patterns.
Geological Context
It typically forms in cavities within volcanic rocks, such as basalt, where silica-rich groundwater deposits successive layers, creating its characteristic bands.
