Quartz Geode

Physical Properties

Hardness: 7 (Mohs scale); Color: White, clear, or tan; Luster: Vitreous to dull (exterior); Crystal Structure: Hexagonal druzy crystals; Cleavage: None; Specific Gravity: 2.65

Formation & Geological History

Formed as hollow cavities in sedimentary or volcanic rock that are filled by the slow precipitation of mineral-rich water over thousands of years.

Uses & Applications

Primarily used as decorative display pieces, for geological education, in jewelry, and for crystal healing collections.

Geological Facts

The word geode comes from the Greek word 'Geoides' meaning earth-like. Unlike a vug, which is a cavity in a rock, a geode is a separate structure that can often be removed from the host rock intact.

Field Identification & Locations

Identify in the field by looking for rounded, bumpy nodules that feel lighter than solid rocks of the same size. Commonly found in deserts and volcanic ash beds in regions like Morocco, Brazil, and the USA (Iowa, Indiana, Utah).

Identified on: 5/2/2026

Mode: Standard