mineral

Druzy quartz geode

Quartz, silicon dioxide (SiO₂), microcrystalline druzy coating

AI-generated identification · may be incorrect

White to cream, sugar-like sparkling crystals lining a cavity; vitreous luster, trigonal crystal structure, no cleavage, conchoidal fracture, Mohs hardness 7, and specific gravity about 2.65. The specimen appears natural but may be cut or polished externally.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater deposits quartz crystals on the walls of a gas cavity or vug in volcanic rock, commonly during late-stage hydrothermal alteration. The exact geological age cannot be determined from the photograph; such geodes range from Paleozoic to Cenozoic.

Uses & applications

Used as a decorative and lapidary specimen, in jewelry, bookends, and mineral collections; quartz is also important in glass, electronics, and industrial abrasives.

Geological facts

“Druzy” describes a dense coating of tiny crystals rather than a separate mineral. Sparkle increases when the surface is illuminated because many crystal faces reflect light.

Field identification & locations

Identify by its cavity lined with tightly packed, hard, glassy quartz crystals that scratch ordinary glass; calcite is softer and may effervesce in dilute acid. Common sources include Brazil, Uruguay, Mexico, Morocco, and the United States.