sedimentary

Black Veined Jasper (Spiderweb Jasper)

Silicon Dioxide (SiO2)

Hardness: 6.5–7 (Mohs scale); Color: Black with white or cream-colored veining; Luster: Vitreous to dull; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None; Specific Gravity: 2.58–2.91.

Hardness: 6
Color: Black with white or cream-colored veining
Luster: Vitreous to dull

Identified March 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the infiltration of silica-rich fluids into volcanic ash or fine-grained sediment. The characteristic 'web' patterning occurs when the stone cracks due to tectonic pressure or dehydration and those cracks are later filled with contrasting mineral deposits like quartz or chalcedony.

Uses & applications

Primarily used as a semi-precious gemstone for jewelry (cabochons, beads), decorative carvings, and as a popular palm stone in the metaphysical and rock collecting communities.

Geological facts

Jasper has been used by ancient civilizations for over 5,000 years. The 'Spiderweb' variety is specifically prized because no two patterns are exactly alike, often resembling a cracked ceramic glaze or a spider's web.

Field identification & locations

Identify in the field by its opaque nature (unlike agate which is translucent) and its high hardness (it will scratch glass). Commonly found in the American Southwest, Mexico, and Africa. For collectors, look for high contrast between the black base and the white webbing.

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