sedimentary
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Hardness: 6.5-7 (Mohs scale); Color: Brownish-red to earthy orange; Luster: Waxy to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
- Hardness
- 6
- Color
- Brownish-red to earthy orange
- Luster
- Waxy to dull
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Brownish-red to earthy orange; Luster: Waxy to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
Formation & geological history
Formed through the accumulation of silica-rich organic remains (like radiolaria or diatoms) or chemical precipitation from groundwater. This specimen shows oxidation from iron impurities.
Uses & applications
Historically used for stone tools and arrowheads; currently used in jewelry (as jasper), landscaping, and as a collector specimen.
Geological facts
Jasper has been used throughout human history; it was a favorite gem in the ancient world, mentioned in the Bible and used extensively in Minoan Crete for seals.
Field identification & locations
Identify in the field by its hardness (it will scratch glass), waxy luster, and conchoidal (shell-like) fracture patterns. Found globally in sedimentary bedding.
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