Properties
| Category | Aggregate rock (impure chalcedony variety) |
|---|---|
| Formula | SiO2 (with varying impurities) |
| Crystal system | Hexagonal |
| Color | Most commonly red, but may be yellow, brown, green or (rarely) blue |
| Crystal habit | Massive |
| Cleavage | none |
| Fracture | Conchoidal |
| Mohs scale hardness | 6.5–7 |
| Luster | Vitreous |
| Diaphaneity | Opaque |
| Specific gravity | 2.5–2.9 |
From the Wikipedia article
Jasper is an opaque type of silica that comes in a variety of colors, most commonly red, yellow, brown, green, and very rarely blue. It is made mostly of very fine-grained quartz or chalcedony, with other minerals contributing to its color and appearance. The common reddish color is due to iron inclusions. Jasper breaks with a smooth surface and is used for ornamentation or as a gemstone. It can be highly polished and is used for items such as vases, jewelry, seals, and snuff boxes. The density of jasper is typically 2.5 to 2.9 g/cm3. Jaspillite is a banded-iron-formation rock that often has distinctive bands of jasper.
Source
Source record: crystal-compendium/jasper/minerals.json. Fetched from English Wikipedia by the operator 2 October 2026.
https://en.wikipedia.org/wiki/Jasper — revision id 1369072425. Text and properties from Wikipedia, licensed CC BY-SA 4.0.