Quartz in Geode
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/65449832@N00">R'lyeh Imaging</a> (CC BY 2.0)
Mineral NameQuartz in Geode
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorscolorless, white, orange, brown
Transparencytranslucent
Type LocalityWorldwide, commonly in volcanic and sedimentary rocks
Mineral GroupSilicates
Usescollector, jewelry, industrial
Associated Mineralschalcedony, calcite, iron oxides
Raritycommon
Description
A macro view of the interior of a geode, revealing translucent to milky white quartz crystals heavily coated with orange-brown iron oxide stains, embedded within a rough, earthy matrix.
Geological Context
Geodes form when mineral-rich fluids deposit layers of silica (quartz and/or chalcedony) and other minerals within cavities in volcanic or sedimentary rocks, often starting from an outer shell of chalcedony.
