igneous
Dalmatian Jasper
Peralkaline Feldspar Rhyolite
Hardness: 5.5 to 7.0 (Mohs); Color: Creamy white or grey with black spots; Luster: Vitreous to dull; Crystal structure: Microcrystalline; Specific gravity: 2.6-2.7.
- Hardness
- 5
- Color
- Creamy white or grey with black spots
- Luster
- Vitreous to dull
Identified More igneous →
Explore Dalmatian Jasper in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5.5 to 7.0 (Mohs); Color: Creamy white or grey with black spots; Luster: Vitreous to dull; Crystal structure: Microcrystalline; Specific gravity: 2.6-2.7.
Formation & geological history
Formed from volcanic activity when lava cools quickly with specific mineral inclusions. The black spots are Arfvedsonite crystals embedded in a feldspar and quartz matrix.
Uses & applications
Used primarily in jewelry (beads, cabochons), ornamental carvings, and by crystal collectors for aesthetic and metaphysical purposes.
Geological facts
Despite being called 'jasper' in the trade, it is technically an igneous rock (rhyolite) rather than a sedimentary jasper. The black spots were long thought to be tourmaline, but are actually a sodic amphibole called arfvedsonite.
Field identification & locations
Identified by its unique spotted pattern resembling a Dalmatian dog. Found most commonly in Chihuahua, Mexico. Collectors should look for the characteristic contrast between the light matrix and dark, distinct spots.
