mineral

Chalcedony-rich agate/jasper

Microcrystalline quartz (SiO₂), likely iron-stained jasper with chalcedony

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; mottled brown, orange, gray, and translucent patches; waxy to dull luster; cryptocrystalline quartz with no cleavage and conchoidal fracture. The rough surface and mixed opacity suggest jasper or brecciated agate rather than a single pure mineral.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rock, depositing chalcedony and quartz; iron oxides create the red-brown coloration. Exact age cannot be determined from the image and depends on its host formation.

Uses & applications

Used as lapidary rough, cabochons, beads, carvings, and decorative stone; attractive pieces are commonly polished or sliced for display.

Geological facts

Agate and jasper are varieties of chalcedony distinguished mainly by translucency and pattern: agate is typically banded or translucent, while jasper is opaque and impure.

Field identification & locations

Test hardness against glass, look for conchoidal fracture, and inspect translucency under strong light; it commonly occurs in volcanic regions worldwide, including Brazil, Mexico, India, Madagascar, and the western United States.