mineral

Quartz Geodes and Crystal Clusters

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Clear, white, smoky, amethyst (purple), and artificially dyed pink/purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None/Conchoidal fracture.

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

Identified June 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities within volcanic or sedimentary rocks. As hydrothermal fluids or groundwater rich in silica permeate these voids, crystals grow inward over time. These vary in age from millions to hundreds of millions of years.

Uses & applications

Commonly used for home decor, educational rock kits, and spiritual/metaphysical collecting. Larger specimens are used in jewelry making.

Geological facts

Geodes look like ordinary rocks on the outside but contain hollow centers filled with crystals. The bright pink specimen in the front is likely a quartz geode that has been artificially dyed to enhance its appeal.

Field identification & locations

Identify by looking for round or oblong nodules that feel lighter than they look (if hollow) or by spotting the characteristic crystal facets in broken pieces. Commonly found in desert regions of Mexico, Morocco, and the USA.

Other mineral specimens

See all

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

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral