mineral

Quartz Geode

Silicon Dioxide (SiO2) within a sedimentary or volcanic shell

Hardness: 7 on Mohs scale; Color: Clear to white internal crystals with a tan/brown exterior shell; Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Luster: Vitreous (glassy)

Identified July 5, 2026More mineral →

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Physical properties

Formation & geological history

Formed via precipitation of mineral-rich water within hollow cavities in sedimentary limestone or volcanic ash. Over thousands of years, quartz crystals grow inward from the outer crust.

Uses & applications

Primarily used as decorative display pieces, educational tools, lapidary specimens, and in metaphysical practices. Larger quartz deposits are used in industrial glass and electronics.

Geological facts

Geodes are often indistinguishable from ordinary rocks on the outside until cracked open. The word geode comes from the Greek word 'Geoides' which means 'earth-like'.

Field identification & locations

Identified by a round, lumpy exterior that feels lighter than a solid rock of the same size. Commonly found in desert regions of the southwestern US, Brazil, and Morocco. Tap the rock; if it sounds hollow, it may be a geode.

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