mineral

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Clear to milky white or off-white translucent crystals lining a light beige outer rind. Luster: Vitreous (glass-like) crystal faces. Crystal structure: Hexagonal prism points within the cavity. Specific gravity: approx 2.65.

Hardness: 7 on Mohs scale
Luster: Vitreous (glass-like) crystal faces

Identified July 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed when mineral-rich hydrothermal fluids precipitate quartz crystals inside hollow cavities in sedimentary limestone/shale or volcanic basalt formations. Over millions of years, crystals grow inward towards the center.

Uses & applications

Popular for lapidary work, mineral display, educational collections, metaphysical practices, and decorative accents.

Geological facts

Geodes appear as unassuming, bumpy round rocks on the outside, but when cracked open they reveal sparkling hollow cavities lined with mineral crystals.

Field identification & locations

Identified by its sparkling crystal cavity (druzy or larger points) and hardness (scratches glass). Commonly found in regions with ancient volcanic activity or limestone beds, such as the Midwestern US (Iowa, Illinois, Indiana), Brazil, and Mexico.