mineral

Quartz Geode

Clear Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Colorless to white; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Colorless to white
Luster: Vitreous (glassy)

Identified March 18, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Colorless to white; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed in cavities (vugs) within volcanic or sedimentary rocks. As hydrothermal fluids rich in silica seep into these hollow spaces, crystals grow inward over thousands to millions of years.

Uses & applications

Primary uses include ornamental decor, metaphysical collecting, and jewelry. In industry, quartz is used in electronics (oscillators), glassmaking, and abrasives.

Geological facts

Geodes are often referred to as 'thunder eggs' when they are filled solid. The word 'geode' comes from the Greek word 'Geoides' meaning 'earth-like'.

Field identification & locations

Identify by its rounded exterior ‘rind’ and hollow interior lined with inward-pointing crystals. Common in desert regions like Morocco, Mexico (Chihuahua), and the US (Iowa, Utah). They are heavier than they look if solid, and lighter if hollow.