igneous
Dalmatian Jasper (or Dalmatian Stone)
Dalmatian Stone (A peralkaline felsite composed of feldspar, quartz, and sodic amphibole)
Hardness: 5.5-7 (Mohs scale); Color: White, cream, or pale grey with distinct black or dark brown spots; Luster: Vitreous to dull; Crystal structure: Microcrystalline; Specific Gravity: Approx 2.6-2.8.
- Hardness
- 5
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 5.5-7 (Mohs scale); Color: White, cream, or pale grey with distinct black or dark brown spots; Luster: Vitreous to dull; Crystal structure: Microcrystalline; Specific Gravity: Approx 2.6-2.8.
Formation & geological history
Formed through volcanic activity where magma cooled quickly, trapping minerals in a fine-grained matrix. It is primarily found in Chihuahua, Mexico. While often called 'Jasper', it is technically an igneous rock (felsite) rather than a sedimentary chalcedony.
Uses & applications
Used primarily in the lapidary arts for beads, cabochons, carvings, and tumbled stones in jewelry making. It is also quite popular in the metaphysical and gemstone collecting communities.
Geological facts
Despite its trade name 'Dalmatian Jasper', it is not a true Jasper (which is a form of chalcedony). The black spots are actually inclusions of Arfvedsonite or other sodic amphiboles, not tourmaline as commonly misidentified.
Field identification & locations
Identify in the field by its unique 'dog-coat' spotted pattern and high hardness (it will not be scratched by a copper penny or steel knife easily). It is almost exclusively sourced from Mexico.
