gemstone

Tumbled amethyst quartz

Quartz, SiO₂; purple coloration from trace iron and irradiation

AI-generated identification · may be incorrect

Likely polished/tumbled pieces with purple to smoky-violet color, vitreous luster, and indistinct fracture; quartz hardness Mohs 7, no cleavage, specific gravity about 2.65. The image is blurred, so exact identification is provisional.

Identified September 15, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, commonly basalt, where quartz crystals grow over long periods; many deposits are Neogene to younger, though quartz is geologically widespread. The pieces have been mechanically tumbled and polished.

Uses & applications

Used for beads, ornaments, cabochons, carvings, and mineral collecting; common tumbled pieces have modest value.

Geological facts

Amethyst is the purple variety of quartz; heating can turn it yellow-orange (citrine). Very dark, nearly black-purple material may be marketed as “Uruguayan” or “African” amethyst, but origin cannot be determined visually.

Field identification & locations

Identify by purple color, glassy luster, hardness, and lack of cleavage; glass or dyed quartz may imitate it. Around 20.1°S, 28.6°E in Zimbabwe, quartz and amethyst are geologically plausible, though the regional source cannot be confirmed from this image.