sedimentary

Geode with Quartz/Chalcedony

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale); Color: Tan, beige, white, and translucent; Luster: Vitreous to waxy; Crystal structure: Trigonal (often microcrystalline or druzy); Specific gravity: approx. 2.65

Hardness: 7 (Mohs scale)
Color: Tan, beige, white, and translucent
Luster: Vitreous to waxy

Identified April 26, 2026More sedimentary →

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Physical properties

Hardness: 7 (Mohs scale); Color: Tan, beige, white, and translucent; Luster: Vitreous to waxy; Crystal structure: Trigonal (often microcrystalline or druzy); Specific gravity: approx. 2.65

Formation & geological history

Formed through the hollow precipitation of mineral-rich groundwater in cavities, such as bubbles in volcanic rock or hollows in sedimentary beds like limestone. This specimen shows a botryoidal or vuggy texture typical of silica precipitation.

Uses & applications

Primary use as a decorative display piece, lapidary material, or educational specimen for mineralogy.

Geological facts

Geodes are essentially 'rock bubbles.' While they look like ordinary rocks on the outside, they often contain hidden crystal cathedrals inside. This specific specimen appears to be an unopened or partially weathered geode nodule.

Field identification & locations

Identify in the field by its round or oblong shape, bumpy exterior texture, and lighter weight compared to solid rocks. Often found in desert regions or limestone quarries.