Agate
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/88422708@N00">zygzee</a> from Coarsegold, US (CC BY 2.0)
Mineral NameAgate
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorswhite, blue, cream, brown, orange
Transparencytranslucent
Type LocalityWorldwide (e.g., Brazil, Uruguay, Mexico)
Mineral GroupSilicates
Usesjewelry, ornamental objects, collector
Associated Mineralsquartz, amethyst, calcite, zeolites
Raritycommon
Description
A polished slice of agate displaying intricate, concentric banding in shades of light blue, cream, brown, and orange, with a smooth, glossy surface.
Geological Context
Agate typically forms in cavities of volcanic rocks, such as basalt, where silica-rich fluids deposit successive layers of chalcedony, often filling voids left by gas bubbles.
