mineral

Quartz Geode

Crystalline Silicon Dioxide (SiO2) in a Geode

Hardness: 7 on Mohs scale; Color: Clear to white interior crystals with a brown or tan outer rind; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture).

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

Identified June 8, 2026More mineral →

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Physical properties

Formation & geological history

Geodes form in cavities within volcanic or sedimentary rocks. Over millions of years, mineral-rich groundwater seeps into these hollows, precipitating crystals onto the inner walls. Most common in regions with ancient volcanic activity.

Uses & applications

Primarily used for decorative display, educational purposes in geology, metaphysical spiritual practices, and as a collector's specimen. Sliced pieces may be used in jewelry.

Geological facts

Geodes are like nature's 'jack-in-the-box'; they look like ordinary rocks on the outside but contain beautiful crystal hidden inside. The word 'geode' comes from the Greek word 'Geoides' meaning earth-like.

Field identification & locations

Identify in the field by looking for rounded, nodular rocks that feel unusually light for their size. Commonly found in desert regions of the SW United States, Brazil, and Mexico. Use a rock hammer to carefully crack them open.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic