Jasper

Physical Properties

Hardness: 6.5-7 (Mohs); Color: Dark green to brown with light veins; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (Conchoidal fracture); Specific gravity: 2.58-2.91

Formation & Geological History

Formed through the deposition of silica from groundwater into cracks or cavities in igneous or sedimentary rocks, often becoming opaque due to high mineral impurity content. Can date back to various geological eras.

Uses & Applications

Primarily used for lapidary work, jewelry (cabochons), interior decoration, and as a popular pocket stone for collectors due to its ability to take a high polish.

Geological Facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek 'iaspis', meaning 'spotted stone'. Since ancient times, it has been valued for its unique patterns and presumed protective qualities.

Field Identification & Locations

Identify in the field by its opacity (even when held to light), high hardness (cannot be scratched by a steel pocketknife), and smooth, waxy feel when tumbled. Common in riverbeds and mountainous regions globally.

Identified on: 4/24/2026

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