Image: <bdi><a href="https://www.wikidata.org/wiki/Q126871366" class="extiw" title="d:Q126871366"><span title="photographer from the United States">Nessa Eull</span></a></bdi> (CC0)
trigonalcommonSilicates
Chalcedony
SiO₂
This specimen is a light brown to tan chalcedony pseudomorph, preserving the intricate structure of a fossilized coral, measuring 11 cm in its longest dimension.
Chalcedony Physical Properties
Mohs Hardness
6.5Crystal System
trigonalLuster
waxyStreak Color
whiteCleavage
noneFracture
conchoidalSpecific Gravity
2.58Colors
white, gray, blue, brown, red, green, tanTransparency
translucentType Locality
Florida, USAMineral Group
SilicatesUses
jewelry, ornamental, collector, industrialAssociated Minerals
calcite, quartzRarity
commonGeological Context
Chalcedony forms in sedimentary environments, often as a secondary mineral, replacing other minerals or organic material like coral through diagenetic processes where silica-rich fluids permeate and replace the original calcium carbonate.
