Rock Identifier
Amethyst stalactite slice pendant (Amethyst (紫 quartz), SiO₂, with concentric quartz/chalcedony and likely agate banding) — mineral
mineral

Amethyst stalactite slice pendant

Amethyst (紫 quartz), SiO₂, with concentric quartz/chalcedony and likely agate banding

AI-generated identification · may be incorrect

Purple quartz crystals radiate from a rounded, banded cavity with pale chalcedony/agate and possible druzy quartz. Quartz hardness is Mohs 7, vitreous luster, trigonal crystal structure, poor cleavage, and specific gravity about 2.65.

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Physical properties

Purple quartz crystals radiate from a rounded, banded cavity with pale chalcedony/agate and possible druzy quartz. Quartz hardness is Mohs 7, vitreous luster, trigonal crystal structure, poor cleavage, and specific gravity about 2.65.

Formation & geological history

Formed when silica-rich fluids filled volcanic vesicles or cavities, depositing chalcedony and later amethyst crystals in concentric layers. Most commercial material comes from Brazil and Uruguay and is generally Cenozoic to Mesozoic in age; the pendant has been cut, polished, and mounted.

Uses & applications

Used as an ornamental gemstone, jewelry, décor, and crystal-collecting specimen. Value depends on color, crystal quality, size, and authenticity.

Geological facts

The purple color is usually caused by iron impurities modified by natural irradiation. The circular banded center suggests an agate-lined amethyst cavity or amethyst geode slice.

Field identification & locations

Identify by its glassy purple quartz crystals, radiating druse, banded chalcedony center, and hardness sufficient to scratch ordinary glass. Common localities include Brazil, Uruguay, Zambia, and Namibia.