sedimentary

Yellow Jasper (Chert variant)

Silicon Dioxide (SiO2) with iron oxide inclusions

Hardness: 6.5-7 (Mohs scale); Color: Opaque yellow to mustard brown; Luster: Vitreous to waxy; Crystal structure: Microcrystalline/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Hardness: 6
Color: Opaque yellow to mustard brown
Luster: Vitreous to waxy

Identified March 24, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of silica-rich micro-organisms or hydrothermal precipitation in volcanic or sedimentary environments. Most specimens range from recent to hundreds of millions of years old.

Uses & applications

Primary use in lapidary arts for cabochons, beads, and therapy stones. Also used as decorative landscaping stone and in jewelry-making for its durability and various patterns.

Geological facts

Jasper has been used as a sacred gemstone for millennia; it was mentioned in the Bible as a 'stone of the High Priest's breastplate.' Yellow jasper specifically gets its color from high concentrations of goethite or limonite (iron oxides).

Field identification & locations

Identify by its opacity (even when held to light), conchoidal fracture, and smooth waxy feel when polished. Commonly found in riverbeds and arid regions such as India, South Africa, and the southwestern United States.

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Sandstone or Siltstone

Arenite (if sandstone)

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Sandstone

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Shale or Slaty Mudstone

Argillaceous sedimentary rock

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Chert Breccia

Brecciated Chert (Microcrystalline Silica)

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Sandstone (Quartz-rich)

Arenite (SiO2)

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Sandstone (with man-made markings)

Arenite (composed primarily of Quartz, SiO2)

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