sedimentary
Chert (Pink Jasper)
Microcrystalline Quartz (SiO2)
Hardness: 7 Mohs scale; Color: Pink, reddish-tan, and mauve; Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 Mohs scale
- Color
- Pink, reddish-tan, and mauve
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 7 Mohs scale; Color: Pink, reddish-tan, and mauve; Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed via the accumulation of silica-rich organic remains or chemical precipitation in marine or groundwater environments. This specimen shows typical conchoidal fracturing common in ancient seafloor deposits.
Uses & applications
Historically used for stone tools (arrowheads, scrapers) due to sharp edges; currently used for lapidary work, landscaping, and as a geological specimen.
Geological facts
Chert is so hard it can strike sparks against steel. The pink coloration is typically caused by trace inclusions of iron oxides or hematite within the silica matrix.
Field identification & locations
Identify by its smooth, shell-like fracture surfaces and extreme hardness (it will scratch glass). Often found in limestone or dolomite beds as nodules or layers.
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