mineral

Quartz-rich chalcedony (likely silicified rock)

Microcrystalline quartz, SiO₂; possibly silicified limestone or jasper

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; cream, tan, gray, and reddish-brown colors with a waxy to dull luster. Massive, cryptocrystalline texture, no obvious cleavage, and conchoidal fracture; translucent edges may occur.

Identified August 13, 2026More mineral →

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Physical properties

Formation & geological history

Formed when silica-rich fluids replaced or filled pores and fractures in an older rock, commonly during diagenesis or hydrothermal alteration. Precise age and host rock cannot be determined from the photograph.

Uses & applications

Used as ornamental stone, carving material, lapidary rough, and occasionally aggregate; attractive pieces may be polished for display.

Geological facts

The cloudy, waxy appearance and irregular reddish-brown veining are typical of chalcedony or jasper-like silicification rather than a single large crystal. A geological classification requires hardness, streak, acid, and thin-section tests.

Field identification & locations

Common in volcanic terrains, sedimentary silica deposits, and hydrothermal zones worldwide. Confirm with a scratch test against glass, inspection for conchoidal fracture, and testing whether dilute hydrochloric acid fizzes on any carbonate host.