mineral

Tumbled chalcedony or quartz-rich stone

Microcrystalline quartz, SiO₂; possibly pale chert or chalcedony

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; cream to honey-yellow, translucent in thin areas, with a dull to waxy luster and no obvious cleavage. The rounded shape indicates natural water wear or tumbling; visible granular texture may also indicate quartz-rich sandstone or calcite-bearing material.

Identified August 10, 2026More mineral →

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Physical properties

Formation & geological history

Quartz-rich silica formed from groundwater deposition in cavities, veins, or sedimentary pores; if chert/chalcedony, formation may range from Paleozoic to Cenozoic depending on locality. The yellow coloration can result from iron staining or included minerals.

Uses & applications

Commonly used for decorative stones, lapidary items, cabochons, and inexpensive jewelry; less commonly for industrial silica if sufficiently pure.

Geological facts

A definitive identification requires hardness, streak, and acid testing: quartz does not fizz in dilute hydrochloric acid, while calcite fizzes strongly and is softer. Its rounded, polished appearance makes locality-based identification difficult.

Field identification & locations

Common in river gravels and silica-rich volcanic or sedimentary terrains worldwide. Check whether it scratches glass, leaves a white streak, and reacts to acid; avoid destructive testing if it is valuable.