mineral

Tumbled yellow chalcedony

Microcrystalline quartz (SiO₂), likely yellow jasper or chalcedony

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; opaque to translucent mustard-yellow, waxy to dull luster, cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The pieces appear polished or tumbled.

Identified August 23, 2026More mineral →

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Physical properties

Hardness 6.5–7 Mohs; opaque to translucent mustard-yellow, waxy to dull luster, cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The pieces appear polished or tumbled.

Formation & geological history

Silica-rich groundwater deposited quartz fibers in cavities or fractures, with iron impurities producing the yellow color; formation may range from Paleozoic to recent depending on source locality. The image alone cannot establish a precise geological age.

Uses & applications

Used as inexpensive cabochons, beads, tumbled stones, carvings, and decorative objects; generally modest collector value.

Geological facts

Yellow chalcedony is commonly confused with yellow jasper; jasper is more opaque and impure, while chalcedony is typically slightly translucent at edges. Color can be natural or enhanced by dye or heat treatment.

Field identification & locations

Identify by its waxy appearance, quartz hardness, lack of cleavage, and resistance to scratching by steel; it should scratch glass but not be scratched by a steel blade. Common sources include Brazil, Madagascar, India, Uruguay, and the United States.