sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with Iron inclusions
Hardness: 6.5-7 (Mohs); Color: Mustard yellow to golden brown; Luster: Waxy to dull; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
- Hardness
- 6
- Color
- Mustard yellow to golden brown
- Luster
- Waxy to dull
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Mustard yellow to golden brown; Luster: Waxy to dull; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
Formation & geological history
Jasper is an opaque variety of chalcedony. It forms as silica-rich fluids permeate through volcanic ash or sedimentary rocks, precipitating in cracks and cavities. This process can happen over millions of years across various geological ages.
Uses & applications
Used primarily in lapidary arts for cabochons, beads, and carvings. Historically used for ornaments and seals; also popular in crystal healing circles and metaphysical collections.
Geological facts
Jasper was a favorite gem in the ancient world; the name can be traced back to Greek, Hebrew, and Persian languages. It is often referred to as a 'spotted or speckled stone' due to its various mineral inclusions.
Field identification & locations
Identify in the field by its opacity (it should not let light through when held to the sun), its smooth waxy feel, and a curved 'conchoidal' fracture when broken. Commonly found in river beds and desert environments.
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