gemstone

Tumbled citrine quartz (probable heat-treated amethyst)

Quartz, silicon dioxide (SiO₂), likely iron-colored citrine

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent yellow to honey-orange, vitreous luster, and conchoidal fracture. Quartz is trigonal and lacks cleavage; the rounded shape indicates tumbling or polishing.

Identified September 8, 2026More gemstone →

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Physical properties

Hardness 7 Mohs; translucent yellow to honey-orange, vitreous luster, and conchoidal fracture. Quartz is trigonal and lacks cleavage; the rounded shape indicates tumbling or polishing.

Formation & geological history

Natural citrine forms when iron-bearing quartz crystallizes in hydrothermal veins or igneous cavities, while most commercial vivid citrine is heat-treated amethyst. Quartz commonly formed in the Precambrian through Cenozoic eras.

Uses & applications

Used as an inexpensive gemstone for cabochons, beads, carvings, and decorative objects; it has little industrial value in this polished form.

Geological facts

The specimen’s opaque, mottled yellow appearance and rounded edges are consistent with tumbled quartz rather than a faceted gem. Natural citrine is generally paler and rarer than treated material.

Field identification & locations

Check for quartz-like glassy luster, hardness sufficient to scratch ordinary glass, and no obvious cleavage; yellow chalcedony or calcite can look similar, so hardness and a gemological test are useful. Common sources include Brazil, Uruguay, Madagascar, and Zambia.