igneous
Dalmatian Jasper
Peralkaline Quartz-Feldspar Porphyry with Arfvedsonite
Mohs hardness: 5.5-7; Color: Creamy white to pale gray with distinct black or dark brown spots; Luster: Vitreous to dull; Crystal structure: Microcrystalline aggregate; Cleavage: None; Specific gravity: 2.58-2.91
- Hardness
- 5
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Mohs hardness: 5.5-7; Color: Creamy white to pale gray with distinct black or dark brown spots; Luster: Vitreous to dull; Crystal structure: Microcrystalline aggregate; Cleavage: None; Specific gravity: 2.58-2.91
Formation & geological history
Formed primarily from volcanic activity in Chihuahua, Mexico. It is an igneous rock composed of feldspar and quartz with inclusions of black amphibole minerals (Arfvedsonite) that create its signature spotted appearance.
Uses & applications
Commonly used for lapidary work, jewelry (beads, cabochons), carvings, and as a popular healing stone in metaphysical circles.
Geological facts
Despite being named 'Jasper', it is geologically not a true jasper (which is sedimentary/chert) but rather an igneous rock. The black spots are specifically arfvedsonite, not tourmaline as often mislabeled.
Field identification & locations
Identify by its unique spotted 'Dalmatian dog' pattern. It is almost exclusively mined in Chihuahua, Mexico. Collectors look for high contrast between the base color and the dark spots.
