igneous

Dalmatian Stone

Peralkaline Quartz-Feldspar Rock with Arfvedsonite

Hardness: 5.5 to 7.5 on the Mohs scale; Color: Creamy white to pale gray base with black spots; Luster: Vitreous to dull; Crystal structure: Monoclinic/Triclinic mixture; Cleavage: None (it is a rock, not a single crystal); Specific gravity: 2.5 to 2.7.

Hardness: 5
Color: Creamy white to pale gray base with black spots
Luster: Vitreous to dull

Identified March 15, 2026More igneous →

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Physical properties

Formation & geological history

Dalmatian stone is an igneous rock formed from the cooling of magma rich in silica. It consists primarily of feldspar and quartz, while the distinctive black spots are inclusions of the amphibole mineral Arfvedsonite. It is primarily found in Chihuahua, Mexico.

Uses & applications

Used extensively in the lapidary arts for making beads, cabochons, and tumbled stones. Due to its unique spotted appearance, it is popular in semi-precious jewelry, home decor, and metaphysical collections.

Geological facts

Commonly mislabeled as 'Dalmatian Jasper', it is actually a peralkaline rock rather than a jasper (which is a form of chalcedony). The black spots were long thought to be tourmaline, but recent studies have confirmed they are Arfvedsonite crystals.

Field identification & locations

Identify in the field by its distinct 'cookies and cream' or 'spotted dog' appearance. It is exclusively sourced from Mexico. Collectors should look for a smooth, matte to glassy texture and sharp contrast between the white matrix and black mineral inclusions.

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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

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