Breccia
Image: <a href="https://en.wikipedia.org/wiki/User:R12347" class="extiw" title="wikipedia:User:R12347">R12347</a> at <a href="https://en.wikipedia.org/wiki/" class="extiw" title="wikipedia:">English Wikipedia</a> (Public domain)
Mineral NameBreccia
Chemical FormulaSiO2 (predominant component)
Mohs Hardness6.5
Streak ColorWhite
CleavageNone
FractureConchoidal
Specific Gravity2.64
Colorsblue, gold, brown, red, black
TransparencyTranslucent to opaque
Type LocalityNamibia, South Africa
Mineral GroupSilicates (as a rock composed primarily of quartz/chalcedony)
Usesjewelry, ornamental, collector
Associated Mineralsquartz, crocidolite
Rarityuncommon
Description
This specimen is Pietersite, a specific type of breccia characterized by its chatoyancy, displaying swirling patterns of golden, blue, and reddish-brown fibers within a quartz matrix.
Geological Context
Pietersite forms from fractured and re-cemented crocidolite (asbestos) that has been replaced by chalcedony, creating a brecciated structure with characteristic chatoyancy.
