mineral

Quartz geode

Microcrystalline quartz and drusy quartz (SiO₂), likely with iron-oxide staining

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous to sugary luster, colorless-to-white crystals with orange-brown iron staining, and a hollow, banded chalcedony/quartz structure. Quartz is trigonal; individual crystals commonly form pointed or granular druse. Exact identification of the brown material would require testing.

Identified September 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed when silica-rich groundwater deposited chalcedony and quartz crystals inside a gas cavity or vug in volcanic rock, generally during cooling and later groundwater circulation. The specimen’s precise geological age and locality cannot be determined from the image.

Uses & applications

Used primarily as a display and collecting specimen; polished geodes and crystal interiors are popular decorative items. Quartz also has major industrial uses in glass, electronics, abrasives, and engineered stone.

Geological facts

The hollow center is a geode cavity, while the sparkling surface is drusy quartz. Orange-brown coloration is commonly caused by iron oxides such as hematite or limonite.

Field identification & locations

Identify by its hollow cavity, hard glassy crystals, quartz sparkle, and inability to scratch quartz with a steel knife; quartz should scratch glass. Common sources include Brazil, Uruguay, Mexico, Morocco, and the United States.