Rock Identifier
Quartz geode fragment (Microcrystalline and drusy quartz, SiO₂, likely in a weathered carbonate or volcanic host) — mineral
mineral

Quartz geode fragment

Microcrystalline and drusy quartz, SiO₂, likely in a weathered carbonate or volcanic host

AI-generated identification · may be incorrect

White to honey-colored drusy crystals with a sparkly vitreous luster and irregular cavities; quartz hardness is 7 Mohs, has no cleavage, conchoidal fracture, and specific gravity about 2.65. The rusty tones likely reflect iron-oxide staining; exact identification is limited by the photograph.

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Physical properties

White to honey-colored drusy crystals with a sparkly vitreous luster and irregular cavities; quartz hardness is 7 Mohs, has no cleavage, conchoidal fracture, and specific gravity about 2.65. The rusty tones likely reflect iron-oxide staining; exact identification is limited by the photograph.

Formation & geological history

Silica-rich fluids deposited quartz crystals inside cavities or fractures, commonly in volcanic rock or limestone; the specimen’s precise age and host rock cannot be determined visually. Similar geodes form from the Paleozoic to recent geological periods.

Uses & applications

Used as a decorative, lapidary, and educational specimen; attractive pieces may be cut, polished, or displayed. It has little industrial value at this small specimen scale.

Geological facts

Drusy quartz consists of many tiny crystals coating a cavity surface, producing the sugar-like sparkle visible here. Iron oxides can produce cream, orange, or brown coloration.

Field identification & locations

Identify by its glittering glassy quartz crystals, hardness, and lack of cleavage; it should scratch glass but not be scratched by a steel knife. Common sources include Brazil, Uruguay, Mexico, Morocco, and the western United States.