sedimentary

Jasp-Agate

Cryptocrystalline Quartz (SiO2) with Iron Oxide inclusions

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: Waxy grey-brown chalcedony with bright red jasper patches; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture).

Hardness: 6
Color: Waxy grey-brown chalcedony with bright red jasper patches
Luster: Vitreous to waxy

Identified June 26, 2026More sedimentary →

Explore Jasp-Agate in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 6.5-7 (Mohs); Color: Waxy grey-brown chalcedony with bright red jasper patches; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture).

Formation & geological history

Formed when silica-rich fluids permeate volcanic or sedimentary rock cavities. The red 'jasper' is caused by iron impurities, while the translucent sections are chalcedony/agate. Often found in volcanic ash beds or gravel deposits.

Uses & applications

Commonly used for lapidary work, cabochons, jewelry, and as decorative pocket stones or healing crystals.

Geological facts

This specimen is a 'bridge' rock, containing both opaque Jasper and translucent Agate. The red color suggests hematite staining within the silica matrix. This material was historically used by indigenous peoples for stone tools due to its controlled fracturing.

Field identification & locations

Identify by looking for translucent edges (agate) mixed with opaque red areas (jasper). It will scratch glass easily. Commonly found in riverbeds or desert washes in the Western United States.