Chalcedony
Image: Koltovoi (CC BY-SA 4.0)
Mineral NameChalcedony
Chemical FormulaSiO2
Mohs Hardness6.5
Crystal Systemtrigonal
Lusterwaxy
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.6
Colorswhite, cream, yellow, orange, brown, reddish-brown
Transparencytranslucent
Type LocalityWorldwide (e.g., Brazil, Uruguay, India, USA)
Mineral GroupSilicates
Usesjewelry, ornamental objects, industrial, collector
Associated Mineralsquartz, calcite, zeolites
Raritycommon
Description
The image displays a cross-section of chalcedony, characterized by intricate banding and botryoidal formations in shades of white, cream, yellow, orange, and reddish-brown. The layers create a cavernous, almost landscape-like appearance within the mineral.
Geological Context
Chalcedony forms from low-temperature hydrothermal solutions, often precipitating in cavities and fissures within volcanic and sedimentary rocks. Its banded varieties, like agate, typically form by rhythmic deposition of silica-rich fluids over time.
