igneous
Dalmatian Jasper
Peralkaline rhyolite with Arfvedsonite inclusions
Hardness: 5.5-7 (Mohs); Color: Pale grey, cream, or beige with black spots; Luster: Vitreous to dull; Crystal structure: Microcrystalline; Specific gravity: 2.5-2.7
- Hardness
- 5
- Color
- Pale grey, cream, or beige with black spots
- Luster
- Vitreous to dull
Identified More igneous →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5.5-7 (Mohs); Color: Pale grey, cream, or beige with black spots; Luster: Vitreous to dull; Crystal structure: Microcrystalline; Specific gravity: 2.5-2.7
Formation & geological history
Formed through the cooling of silica-rich volcanic magma (rhyolite). The dark spots are actually inclusions of the mineral arfvedsonite, not tourmaline as often mistakenly claimed.
Uses & applications
Primarily used for lapidary work, jewelry making (cabochons, beads), decorative carvings, and metaphysical/collecting purposes.
Geological facts
Despite being called a 'Jasper', it is technically an igneous rock (rhyolite). It is named after the Dalmatian dog breed because of its distinct black-on-white spotted appearance.
Field identification & locations
Identify in the field by its distinct cream background and rounded black spots. It does not react to acid and is found almost exclusively in Chihuahua, Mexico.
