mineral

Tumbled quartz varieties

Quartz (SiO₂), likely milky quartz and/or chalcedony

AI-generated identification · may be incorrect

Hardness 7 Mohs; vitreous to waxy luster, white to translucent cream, with no visible cleavage and conchoidal fracture. The rounded surfaces indicate tumbling; the upper piece may be translucent chalcedony or milky quartz, while the clearer piece is quartz.

Identified September 4, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich igneous, hydrothermal, and metamorphic fluids; chalcedony forms as microcrystalline silica in cavities and veins. Quartz is abundant from Precambrian rocks to the present day.

Uses & applications

Used for decorative stones, carvings, abrasives, glass, electronics, and gemstone cabochons. Common tumbled pieces generally have modest commercial value.

Geological facts

Quartz is the second-most abundant mineral in Earth’s continental crust and is piezoelectric. Milky appearance results from microscopic fluid inclusions, fractures, or dispersed impurities.

Field identification & locations

Identify by glassy/waxy luster, lack of cleavage, conchoidal fracture, and resistance to scratching by a steel knife; quartz should scratch ordinary glass. Common worldwide, especially in Brazil, Madagascar, the United States, and quartz veins.