Jasper
Silicate (chalcedony) · SiO₂
Jasper is an opaque, iron-rich variety of chalcedony in earthy reds, yellows and browns, prized for its patterns when cut and polished.
What is jasper?
Jasper is opaque microcrystalline quartz coloured by iron oxides and other impurities. Unlike translucent agate, jasper is solid and opaque, often in bold reds, mustard yellows and browns, sometimes with picture-like patterns. It is abundant, tough and a staple of lapidary work.
Properties
- Chemical formula
- SiO₂
- Category
- Silicate (chalcedony)
- Hardness (Mohs)
- 6.5–7
- Crystal system
- Trigonal (microcrystalline)
- Lustre
- Dull to waxy
- Streak
- White
- Colour
- Red, yellow, brown, green, mixed
- Cleavage / fracture
- None; conchoidal fracture
How to identify jasper
- →Opaque, not translucent even on thin edges.
- →Hardness near 7, scratches glass, dull to waxy lustre.
- →Earthy red, yellow, brown or green, often patterned.
- →Breaks with a smooth conchoidal fracture.
Where jasper is found
Jasper is common worldwide. Notable material comes from Oregon and Idaho (USA), India, Australia and South Africa.
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