
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides (Goethite)
AI-generated identification · may be incorrectHardness: 6.5-7 (Mohs scale); Color: Opaque yellow to mustard brown; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91.
- Hardness
- 6
- Color
- Opaque yellow to mustard brown
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Opaque yellow to mustard brown; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91.
Formation & geological history
Formed from the deposition of silica from water-rich environments like thermal springs or during the sedimentation of volcanic ash and silicate-rich fluids. It can date from various geological periods, often millions of years old, typically found in hydrothermal veins or sedimentary beds.
Uses & applications
Primarily used in jewelry (beads, cabochons), lapidary art, and ornamental carvings. Historically used for making tools and as a decorative stone in ancient architecture.
Geological facts
Jasper is an impure variety of silica; the yellow color is specifically caused by the presence of Goethite or other iron oxides. In ancient times, it was called the 'rain bringer' and was believed to protect travelers.
Field identification & locations
Identify in the field by its opaque nature (unlike translucent chalcedony), smooth waxy feel when weathered, and hardness (it will scratch glass). Commonly found in riverbeds or desert regions of India, Russia, Brazil, and the USA.
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