mineral

Pink chalcedony (likely agate/quartz geode fragment)

Microcrystalline quartz, SiO₂; chalcedony with possible iron-oxide inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; pale pink to salmon color, generally waxy to dull luster, cryptocrystalline quartz structure, no cleavage, conchoidal fracture, specific gravity about 2.6. The rough gray-brown rind and translucent pink interior are characteristic of a silica nodule or geode fragment.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich groundwater deposited layered chalcedony in a cavity or vesicle, commonly in volcanic rock; pink coloration may result from iron oxides or other trace impurities. Such material commonly formed during the Cenozoic or older volcanic episodes, but the exact age cannot be determined visually.

Uses & applications

Used for cabochons, carvings, polished slices, beads, and decorative specimens; durable chalcedony is also used in jewelry and ornamental objects.

Geological facts

Chalcedony is quartz composed of extremely small interlocking crystals, unlike visibly crystalline amethyst or quartz. A flashlight may reveal translucency and internal banding.

Field identification & locations

Identify by its hardness, waxy translucent appearance, conchoidal fracture, and inability to scratch it with a steel knife; it should scratch glass. Common sources include Brazil, Uruguay, Mexico, India, Madagascar, and the western United States.