sedimentary

Jasper

Silicon Dioxide (SiO2) with impurities (mostly Iron Oxides)

Hardness: 6.5-7 (Mohs scale); Color: Typically red, brown, or yellow; Luster: Dull to vitreous; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.91

Hardness: 6
Color: Typically red, brown, or yellow
Luster: Dull to vitreous

Identified March 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from volcanic ash or water circulation through sediment during the Proterozoic to Cenozoic eras. The red coloring is caused by iron inclusions (Hematite) oxidizing during the formation process.

Uses & applications

Commonly used in lapidary work for cabochons, beads, and carvings. Historically used for making tools due to its conchoidal fracture, and currently popular for 'healing' stones and jewelry.

Geological facts

Jasper was a favorite gem in the ancient world, mentioned in multiple historical texts including the Bible. It is a variety of chalcedony, which is a cryptocrystalline form of quartz.

Field identification & locations

Identify in the field by its opaque nature (even when held to light), high hardness (cannot be scratched by a steel knife), and smooth, shell-like fracture pattern. Often found in riverbeds or near volcanic deposits.

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