Jasper
Chalcedony (quartz)JewelryWiki Editorial·2 sources·Reviewed 2026-08-04
Opaque chalcedony, coloured and patterned by the mineral impurities trapped in it — which is why jasper is sold under dozens of trade names describing a look rather than a material. It is the same hardness as agate and carnelian, and the difference is simply that jasper is opaque where they are translucent.
Properties
| Property | Value | Authority |
|---|---|---|
| Mohs hardness | 7 [1] | — |
| Specific gravity | 2.55–2.91 [1] | — |
| Chemical formula | SiO2 Read from the species entry, Chalcedony. A variety shares its species’ formula. [2] | — |
| Crystal system | Hexagonal (trigonal), microcrystalline [1] | — |
| Common treatments | Dyeing, per IGS’s list of chalcedony treatments. [1] | — |
| Care cautions | Durable enough for everyday wear. If the colour is improbably vivid, treat it as dyed and keep it from solvents and strong light. [1] | — |
Sources
- International Gem Society — gemstone articles — International Gem Society (IGS, gemstone information articles (gemsociety.org))
- Handbook of Mineralogy — Mineral Data Publishing / Mineralogical Society of America (Handbook of Mineralogy, Mineral Data Publishing)