mineral

Tumbled pale chalcedony, possibly common opal

Microcrystalline quartz (SiO₂), with possible hydrous silica (opal-A)

AI-generated identification · may be incorrect

Smooth, rounded, translucent milky-white to pale peach body with a waxy-to-glassy luster; likely Mohs hardness 6.5–7 if chalcedony, or 5.5–6.5 if opal. No visible cleavage; cryptocrystalline or amorphous structure, with approximate specific gravity 2.0–2.65.

Identified August 18, 2026More mineral →

Explore Tumbled pale chalcedony, possibly common opal in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Chalcedony forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks; opal forms from hydrated silica gel. Geological ages range widely, from recent deposits to ancient volcanic and sedimentary formations.

Uses & applications

Used as a lapidary stone for polished specimens, cabochons, beads, and ornamental objects; this small tumbled piece has modest commercial value.

Geological facts

The soft translucence and subtle peach coloration may result from iron impurities or internal diffusion. A definitive distinction from opal requires hardness, specific-gravity, or microscopic testing.

Field identification & locations

Common sources include Brazil, Uruguay, Mexico, Madagascar, Australia, and the western United States. Identify chalcedony by its waxy translucence and resistance to steel scratching; avoid destructive testing on polished pieces.