Quartz Geode
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Mineral NameQuartz Geode
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorscolorless, white, grey, purple
Transparencytransparent
Type LocalityWorldwide
Mineral GroupSilicates
Usesornamental, collector, jewelry
Associated Mineralschalcedony, calcite, celestite
Raritycommon
Description
A hollow, rounded rock formation lined with inward-pointing quartz crystals, often colorless, white, or purple, encased in a duller outer rock layer.
Geological Context
Geodes form in volcanic or sedimentary rocks when mineral-rich water seeps into a cavity, depositing layers of silica and other minerals, which then crystallize inwards over time.
