mineral
Dyed or coated quartz geode
Quartz geode; silicon dioxide (SiO₂), likely artificially color-enhanced
AI-generated identification · may be incorrectHardness 7 Mohs; typically white to gray chalcedony outer rind with sparkling drusy quartz lining. Vitreous to sugary luster, trigonal quartz crystals, and no prominent cleavage; vivid blue, red, green, and orange colors strongly indicate dye or coating.
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Physical properties
Hardness 7 Mohs; typically white to gray chalcedony outer rind with sparkling drusy quartz lining. Vitreous to sugary luster, trigonal quartz crystals, and no prominent cleavage; vivid blue, red, green, and orange colors strongly indicate dye or coating.
Formation & geological history
Geodes form when gas cavities in volcanic rocks are later lined by chalcedony and quartz from groundwater. This specimen is likely a commercially processed geode, commonly sourced from Brazil or Uruguay; its original formation may range from Mesozoic to Cenozoic depending on locality.
Uses & applications
Used mainly as a decorative or educational specimen and inexpensive mineral display piece; untreated quartz geodes have modest collecting value.
Geological facts
The multicolored zoning is not typical of natural quartz and is commonly produced by soaking or surface treatment. A white, gray, or tan rind surrounding a hollow, sparkly interior is characteristic of a geode.
Field identification & locations
Identify it by the hollow cavity, banded chalcedony rind, and drusy quartz crystals; dye may concentrate in cracks and porous areas. Common sources include Brazil, Uruguay, Mexico, and Morocco.
