mineral

Quartz-rich chalcedony (likely jasper or agate)

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

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent gray, honey, amber, and reddish-brown; waxy to vitreous luster; cryptocrystalline quartz with no cleavage and conchoidal fracture. The irregular banding and iron staining suggest brecciated or jaspery chalcedony rather than a single clear crystal.

Identified August 24, 2026More mineral →

Explore Quartz-rich chalcedony (likely jasper or agate) 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

Forms when silica-rich groundwater fills cavities, fractures, or vesicles in volcanic rock, later cementing and incorporating iron oxides; commonly Cenozoic to older, depending on host rock. Exact age and locality cannot be determined from the photograph.

Uses & applications

Used as ornamental stone, cabochons, carvings, beads, and lapidary material; tougher opaque portions are sold as jasper or agate. Suitable for polished décor but not typically high-value gem material.

Geological facts

Chalcedony is quartz whose crystals are too small to see individually; iron oxides create the orange, yellow, and red colors. Acid does not visibly react, unlike calcite.

Field identification & locations

Look for waxy luster, translucency at thin edges, hardness sufficient to scratch glass, and conchoidal fracture; agate usually shows clearer curved banding, while jasper is more opaque. Common worldwide, especially in volcanic regions.