igneous

Dalmatian Stone (commonly called Dalmatian Jasper)

Peralkaline Rock (mixed Feldspar, Quartz, and Arfvedsonite)

Hardness: 5.5-7 (Mohs); Color: Pale grey or cream base with distinct black or dark green circular spots; Luster: Dull to vitreous; Crystal Structure: Microcrystalline; Specific Gravity: 2.58-2.91

Hardness: 5
Luster: Dull to vitreous

Identified March 22, 2026More igneous →

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Physical properties

Hardness: 5.5-7 (Mohs); Color: Pale grey or cream base with distinct black or dark green circular spots; Luster: Dull to vitreous; Crystal Structure: Microcrystalline; Specific Gravity: 2.58-2.91

Formation & geological history

Formed through the cooling of silica-rich magma that has been enriched with alkali metals. It is an igneous peralkaline rock where the black spots are formed by the presence of arfvedsonite or other amphiboles rather than tourmaline. Most commercial deposits originate from Chihuahua, Mexico.

Uses & applications

Used primarily in the lapidary arts for beads, cabochons, carvings, and tumbled stones. It is popular in the metaphysical community and used for ornamental jewelry.

Geological facts

Despite being called 'Dalmatian Jasper', it is not actually a jasper (which is a sedimentary microcrystalline quartz) but rather an igneous rock. The black spots were long mistaken for Tourmaline, but scientific analysis has proven them to be the mineral Arfvedsonite.

Field identification & locations

Identify in the field by its unique 'dog-spot' pattern which is remarkably consistent. It is almost exclusively mined in Mexico. Collectors should look for high contrast between the cream base and the dark spots with minimal brown staining.

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Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous

Magnetite

Iron(II,III) oxide (Fe3O4)

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Magnetite (Fe3O4)

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