sedimentary

Jasper-Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Hardness: 6.5-7 Mohs; Color: Muted white, yellow, orange and brown; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline Cryptocrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.64

Hardness: 6
Color: Muted white, yellow, orange and brown
Luster: Waxy to vitreous

Identified June 27, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from silica-rich groundwater percolating through porous volcanic rock or sedimentary layers. The silica precipitates out of solution to form banded or opaque masses over millions of years, often in volcanic ash beds or limestone cavities.

Uses & applications

Used primarily for lapidary work, jewelry making (cabochons), interior decoration, and as a collectible metaphysical stone.

Geological facts

Jasper and Agate are both varieties of chalcedony. While Agate is translucent and banded, Jasper is opaque due to higher mineral impurities. This specimen shows a transition between the two, often referred to as Jasp-agate.

Field identification & locations

Identify in the field by its waxy appearance when wet and its inability to be scratched by a steel knife. It is commonly found in riverbeds and coastal areas where the surrounding softer rock has eroded away.

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