igneous
Dalmatian Jasper
Peralkaline Quartz-Feldspar Rock with Arfvedsonite
Hardness: 5.5-7 (Mohs scale), Color: Creamy white to gray with black or dark brown spots, Luster: Vitreous to dull, Crystal Structure: Trigonal/Microcrystalline, Specific Gravity: 2.6-2.7
- Hardness
- 5
Identified More igneous →
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Physical properties
Hardness: 5.5-7 (Mohs scale), Color: Creamy white to gray with black or dark brown spots, Luster: Vitreous to dull, Crystal Structure: Trigonal/Microcrystalline, Specific Gravity: 2.6-2.7
Formation & geological history
Dalmatian Jasper is an igneous rock that forms from the slow cooling of magma. The characteristic 'spots' are actually inclusions of arfvedsonite (a sodic amphibole) or rarely tourmaline. It is primarily found in Chihuahua, Mexico.
Uses & applications
Mainly used for lapidary purposes including beads, cabochons, carvings, and ornamental jewelry. It is also popular in holistic practices and stone collecting due to its unique pattern.
Geological facts
Commonly misidentified as a jasper (which is sedimentary), it is actually an igneous rock composed mainly of quartz and feldspar. Its name comes from its resemblance to the Dalmatian breed of dog.
Field identification & locations
Identify by the distinct black spots on a white-tan background; the spots are typically circular and evenly distributed. It is most commonly found in Mexico. Collectors should look for sharp contrast between the matrix and the spots.
