sedimentary
Jasper (Banded Jasper)
Silicon Dioxide (SiO2) with impurities
Hardness: 6.5-7 (Mohs scale), Color: Red, brown, and yellowish-tan bands, Luster: Vitreous to dull, Crystal Structure: Microcrystalline/Cryptocrystalline (Trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Red, brown, and yellowish-tan bands, Luster: Vitreous to dull, Crystal Structure: Microcrystalline/Cryptocrystalline (Trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the deposition of silica from water solutions or volcanic ash into sedimentary environments. The red bands are typically caused by iron oxide (hematite) inclusions. It can form in various geological ages during the silicification of sediments.
Uses & applications
Used primarily for lapidary work, jewelry (cabochons and beads), decorative ornaments, and as a popular collector's item due to its unique patterns.
Geological facts
Jasper is a variety of chalcedony. The name comes from the Greek word 'iaspis', meaning 'spotted stone'. It is known for its opacity and unique color patterns that often mimic landscapes or bands.
Field identification & locations
Identify in the field by its hardness (will scratch glass), opaque nature, and smooth, waxy feel when water-worn. Common in riverbeds, beaches, and areas with ancient volcanic or sedimentary activity.
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