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 March 4, 2026More igneous →

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Physical properties

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.

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Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

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)

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Blue Apatite

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

mineral

Magnetite

Magnetite (Fe3O4)

mineral