mineral

Amethyst/Smoky Quartz Cluster

Silicon Dioxide (SiO2) with iron and aluminum impurities

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale), Color: Pale purple (amethyst) transitioning to brownish-grey (smoky), Luster: Vitreous/glassy, Crystal structure: Trigonal (hexagonal prisms), Cleavage: None/Conchoidal fracture, Specific gravity: 2.65

Identified July 3, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or cavities (vugs) within igneous rocks like granite or volcanic geodes through the cooling of silica-rich fluids. The purple color comes from irradiation of iron impurities, while the smoky tint results from irradiation of aluminum impurities.

Uses & applications

Primarily used as a decorative display specimen, in lapidary work for cabochons or beads, and highly valued by metaphysical collectors and rockhounds.

Geological facts

The specimen shows a transition between amethyst and smoky quartz; such bicolored crystals are common in specific localities like Jackson's Crossroads in Georgia, USA, or certain Brazilian mines. Amethyst was once considered a cardinal gem alongside diamonds and rubies until large deposits were found in South America.

Field identification & locations

Identify in the field by its distinct hexagonal crystal habit, vitreous luster, and lack of cleavage. It is commonly found in geodes and pegmatites. Collectors look for clarity, depth of color, and the presence of undamaged termination points on the crystal faces.