Jasper
Image: Aagnverglaser (CC BY-SA 4.0)
Mineral NameJasper
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lusterdull
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorsreddish-brown, red, brown, yellow, green
Transparencyopaque
Type LocalityWidespread
Mineral GroupSilicates
Usesjewelry, ornamental stone, carving material
Associated Mineralsquartz, chalcedony, agate, opal
Raritycommon
Description
An opaque, microcrystalline variety of quartz, typically reddish-brown with banding, and a rough, unpolished surface as seen in the image.
Geological Context
Jasper forms in various geological environments, including volcanic rocks, hydrothermal veins, and sedimentary deposits, often as a result of silica-rich solutions replacing other minerals or filling voids. It is commonly found in association with chert and other cryptocrystalline silica deposits.
