mineral

Quartz crystal

Quartz (SiO₂), likely milky or iron-stained quartz

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent, pale cream to colorless, with vitreous luster and irregular/conchoidal fracture. It lacks prominent cleavage and has a trigonal crystal structure; the visible planar faces may be fracture or crystal surfaces.

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, pegmatites, and igneous or metamorphic rocks over a wide range of geological ages. The yellow-brown coloration is commonly caused by iron-oxide staining or inclusions.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, electronics, and engineered stone; clear attractive crystals are sold as inexpensive mineral specimens. This piece appears rough and modestly collectible.

Geological facts

Quartz is one of Earth’s most abundant minerals and is highly resistant to weathering, making it common in sand and sediment. A scratch test against glass can help confirm its hardness, though testing may damage the specimen.

Field identification & locations

Identify it by hardness, glassy luster, lack of cleavage, and translucent appearance; common localities include pegmatites, hydrothermal veins, and quartz-rich metamorphic rocks worldwide. Estimated value: $1–$10 for a small common specimen, potentially higher if crystal faces or unusual inclusions are present.