Quartz Geode (partially formed)
Silicon Dioxide (SiO2)
Rock Type: mineral

Physical Properties
Hardness: 7 (Mohs scale), Color: Smoky brown to translucent white, Luster: Vitreous to dull (external shell), Crystal Structure: Trigonal, Cleavage: None/Conchoidal fracture, Specific Gravity: 2.65
Formation & Geological History
Formed when mineral-rich hydrothermal fluids seep into cavities in volcanic or sedimentary rocks. Over time, crystals grow inward. Typically occurs in vesicles of basalt or limestone cavities.
Uses & Applications
Commonly used for geological study, home decor, meditation/metaphysical purposes, and as entry-level mineral specimens for collectors.
Geological Facts
Geodes can range from the size of a marble to several meters across. This specimen shows a 'vug,' which is a small cavity within a rock lined with crystals.
Field Identification & Locations
Identify by looking for a bumpy, roundish exterior that is lighter than expected for its size. In the field, shaking a geode may sometimes reveal loose crystals rattling inside. Commonly found in desert regions or near volcanic ash deposits.
Identified on: 4/20/2026
Mode: Standard