mineral

Quartz Geode (Unbroken)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Off-white, greyish, crystalline exterior. Luster: Vitreous to dull exterior with sparkly sugary quartz crystals. Structure: Trigonal/Hexagonal quartz crystals forming a rounded nodule shell.

Hardness: 7 on Mohs scale
Color: Off-white, greyish, crystalline exterior

Identified July 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed in sedimentary rocks or volcanic cavities where silica-rich groundwater precipitated mineral crystals inward over thousands to millions of years, leaving a hollow or crystalline sphere.

Uses & applications

Popular among lapidary hobbyists, rockhounding collectors, and decorative display items (especially when cracked open or sawn into halves).

Geological facts

Geodes look like ordinary rounded, rough rocks on the outside, but can contain sparkling quartz, amethyst, or agate crystals inside when cracked open or cut.

Field identification & locations

Identify by its rounded, cauliflower-like texture and light weight relative to its size (if hollow inside). Commonly found in riverbeds, limestone formations, and volcanic ash beds in regions like the American Midwest (Iowa, Missouri, Indiana) and Brazil.