Jasper

Physical Properties

Hardness: 6.5-7 (Mohs); Color: Reddish-brown, earthy tones; Luster: Dull to vitreous; Crystal Structure: Microcrystalline/Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Formation & Geological History

Formed from the deposition of silica from water solutions or volcanic ash, occurring in varied geological ages from Precambrian to recent times. This specimen appears as a water-worn river pebble.

Uses & Applications

Used primarily in lapidary arts, jewelry, as a decorative gemstone, and historically for making tools due to its hardness and ability to hold an edge.

Geological Facts

Jasper’s name comes from the Greek word 'iaspis', meaning spotted stone. It is an opaque variety of chalcedony that contains up to 20% mineral impurities which provide its diverse colors.

Field Identification & Locations

Identify in the field by its hardness (it will scratch glass), its opaque nature when held to light, and its smooth, waxy feel when polished by water. It is a common find in riverbeds and gravel pits.

Identified on: 4/15/2026

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