igneous
Dalmatian Jasper
Peralkaline Rhyolite (composed of Quartz, Feldspar, and Arfvedsonite)
Hardness: 6.5-7 (Mohs); Color: Creamy white to pale gray with black or dark brown spots; Luster: Vitreous to dull; Crystal structure: Microcrystalline; Specific gravity: 2.6-2.7
- Hardness
- 6
- Color
- Creamy white to pale gray with black or dark brown spots
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Creamy white to pale gray with black or dark brown spots; Luster: Vitreous to dull; Crystal structure: Microcrystalline; Specific gravity: 2.6-2.7
Formation & geological history
Dalmatian Jasper is an igneous rock formed when magma cool and crystallizes. The unique spots are actually inclusions of arfvedsonite (an amphibole mineral) rather than tourmaline as often mistakenly claimed. It primarily forms in volcanic regions of Mexico.
Uses & applications
Used extensively in the jewelry industry for beads, cabochons, and carvings. It is also a very popular stone for collectors and metaphysical practitioners.
Geological facts
Despite being called a 'Jasper', it is geologically an igneous rhyolite rather than a sedimentary chalcedony. It is named for its resemblance to the Dalmatian dog breed.
Field identification & locations
Identified by its distinctive speckled appearance resembling a Dalmatian dog. Primarily found in Chihuahua, Mexico. To identify, check for the characteristic cream base with well-defined black spots that do not scratch easily with a steel knife.
