mineral

Agate slice or chalcedony pebble

Microcrystalline quartz (SiO₂), likely botryoidal or banded chalcedony/agate

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent cream, tan, and gray with waxy to vitreous luster. It has cryptocrystalline quartz structure, no obvious cleavage, and typical specific gravity near 2.6.

Identified August 19, 2026More mineral →

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Physical properties

Hardness 6.5–7 Mohs; translucent cream, tan, and gray with waxy to vitreous luster. It has cryptocrystalline quartz structure, no obvious cleavage, and typical specific gravity near 2.6.

Formation & geological history

Forms when silica-rich groundwater fills cavities in volcanic rock, depositing chalcedony and quartz in layers over time. The specimen is likely polished or naturally water-worn; its exact geological age and locality cannot be determined from the image.

Uses & applications

Used for cabochons, beads, carvings, lapidary objects, and mineral collections; agate is also used decoratively and occasionally for small industrial components.

Geological facts

Agate’s colors and banding commonly result from trace iron and repeated changes in fluid chemistry during cavity filling.

Field identification & locations

Identify by its waxy translucence, hardness, curved fracture, and possible internal banding; it should scratch glass but not be scratched by a steel knife. Common sources include Brazil, Uruguay, Mexico, India, and the United States.