igneous
Dalmatian Jasper
Dalmatian Stone (a microcrystalline quartz and feldspar rock with arfvedsonite)
Hardness: 5.5-7 (Mohs scale); Color: Creamy white or gray background with black or dark brown spots; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.91
- Hardness
- 5
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 5.5-7 (Mohs scale); Color: Creamy white or gray background with black or dark brown spots; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.91
Formation & geological history
Formed primarily from volcanic activity in Mexico, it is a peralkaline rock consisting of a mixture of feldspar and quartz (the matrix) with black spots composed of the amphibole mineral arfvedsonite.
Uses & applications
Commonly used in lapidary work for beads, cabochons, carvings, and ornamental objects. It is also popular in holistic practices and as a collector's stone due to its unique pattern.
Geological facts
Despite being marketed as 'Jasper,' it is technically an igneous rock rather than a sedimentary chalcedony. The name comes from its resemblance to the Dalmatian dog breed.
Field identification & locations
Identified by its distinctive 'spotted' appearance that remains consistent through the material. Primarily found in Chihuahua, Mexico. For identification, look for the high-contrast black arfvedsonite spots against a lighter peralkaline background.
