sedimentary (chemically precipitated mineral)
Jasper (likely a variety of Yellow or Mustard Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Hardness: 6.5-7.0 (Mohs scale), Color: Mustard yellow to brownish-orange with dark inclusions, Luster: Waxy to vitreous, Crystal structure: Trigonal/Microcrystalline, Cleavage: None (conchoidal fracture), Specific gravity: 2.58-2.91
- Hardness
- 6
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7.0 (Mohs scale), Color: Mustard yellow to brownish-orange with dark inclusions, Luster: Waxy to vitreous, Crystal structure: Trigonal/Microcrystalline, Cleavage: None (conchoidal fracture), Specific gravity: 2.58-2.91
Formation & geological history
Formed via the deposition of silica from water-rich environments, often in volcanic ash beds or hydrothermal veins where mineral impurities like iron oxides create the yellow/brown coloration. Can range from Tertiary to Precambrian in age depending on the deposit site.
Uses & applications
Used primarily for lapidary work (cabochons), jewelry, decorative carvings, and as a collector's specimen. In industry, high-purity silicas have historical use in flint-knapping for tools.
Geological facts
Jasper is an opaque variety of chalcedony. The name 'Jasper' is derived from the Greek word 'iaspis', meaning spotted stone. It is often found in large boulders and varies greatly in appearance based on the trace minerals present during formation.
Field identification & locations
Identify in the field by its waxy luster, smoothness when wet, and lack of transparency. It will scratch glass but cannot be scratched by a steel knife. Common in the Pacific Northwest (USA), India, and Madagascar. Look for the characteristic smooth, shell-like (conchoidal) fracture surfaces.
More like this
Other sedimentary (chemically precipitated mineral) specimens
Jasper (likely Polychrome or Desert Jasper)
Silicon Dioxide (SiO2) with impurities
sedimentary (chemically precipitated mineral)
Turquoise
Hydrated phosphate of copper and aluminium - CuAl6(PO4)4(OH)8·4H2O
mineral
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
mineral
Chert (Jasper/Jasperoid)
Chert (chemically precipitated microcrystalline Quartz, SiO2)
sedimentary
Tufa
Calcareous Tufa (Calcium Carbonate, CaCO3)
sedimentary
Gold Ore
Native Gold (Au)
mineral