sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5–7 (Mohs scale); Color: Reddish-brown, tan, and earthy tones; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Fracture: Conchoidal; Specific gravity: 2.58–2.91

Hardness: 6
Color: Reddish-brown, tan, and earthy tones
Luster: Vitreous to dull

Identified April 4, 2026More sedimentary →

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Physical properties

Formation & geological history

Usually forms when fine particulate materials (often silica-rich) settle in volcanic ash or sedimentary environments. It is a variety of chalcedony that contains impurities such as iron oxides, which give it its distinctive earthy colors.

Uses & applications

Used primarily as a gemstone for jewelry (cabochons), ornamental stone, and in lapidary art. Historically used for making tools and seals.

Geological facts

Jasper has been used by ancient civilizations for thousands of years. It is mentioned in various historical texts and was often used in the seals of ancient Babylon and Egypt. Pieces are often uniquely patterned, earning nicknames like 'Picture Jasper'.

Field identification & locations

Identify in the field by its hardness (it can scratch glass), its opaque nature, and its smooth, waxy fracture surface. It is extremely common in desert environments and river beds in the Western United States and India.