igneous

Dyed Dalmatian Jasper (Dalmatian Stone)

Perthitic Feldspar with Arfvedsonite inclusions

Hardness: 5.5 to 7.0 Mohs; Color: Naturally white with black spots (here dyed bright blue); Luster: Vitreous to dull; Crystal structure: Monoclinic/Triclinic; Specific gravity: 2.5–2.7

Hardness: 5
Color: Naturally white with black spots (here dyed bright blue)
Luster: Vitreous to dull

Identified May 21, 2026More igneous →

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Physical properties

Hardness: 5.5 to 7.0 Mohs; Color: Naturally white with black spots (here dyed bright blue); Luster: Vitreous to dull; Crystal structure: Monoclinic/Triclinic; Specific gravity: 2.5–2.7

Formation & geological history

Formed from slow-cooling igneous magma where alkali feldspar and quartz crystallize, capturing tourmaline or arfvedsonite to create the distinct spots. Most specimens originate from Mexico.

Uses & applications

Used primarily in the lapidary arts for beads, cabochons, carvings, and tumbled stones for jewelry and metaphysical collecting.

Geological facts

Despite being called a 'Jasper' in the trade, it is technically an igneous rock composed of feldspar and quartz, not a microcrystalline silicate jasper. The black spots were long thought to be Tourmaline but are actually the amphibole mineral Arfvedsonite.

Field identification & locations

Identify by its 'dalmatian' spot pattern. In this case, the vibrant blue color indicates it has been artificially dyed, a common treatment for this specific stone to increase commercial appeal. Found globally but mostly mined in Chihuahua, Mexico.

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Blue Apatite

Fluorapatite (Ca5(PO4)3F)

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Dark Igneous Rock (Likely Basalt or Diabase)

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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Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

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Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

mineral

Magnetite

Magnetite (Fe3O4)

mineral