igneous
Dalmatian jasper (often sold as Dalmatian stone)
Porphyritic quartz monzonite or alkali granite, composed mainly of feldspar and quartz with black aegirine/arfvedsonite amphibole-group minerals
AI-generated identification · may be incorrectCream to pale gray, opaque, fine-grained matrix with rounded black spots; polished/tumbled surface and typically vitreous to dull luster. Mohs hardness about 6–7; massive, with no obvious cleavage in the finished piece; specific gravity roughly 2.6–2.7.
Identified More igneous →
Explore Dalmatian jasper (often sold as Dalmatian stone) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Cream to pale gray, opaque, fine-grained matrix with rounded black spots; polished/tumbled surface and typically vitreous to dull luster. Mohs hardness about 6–7; massive, with no obvious cleavage in the finished piece; specific gravity roughly 2.6–2.7.
Formation & geological history
An alkaline silica-rich igneous rock formed by slow cooling of magma, likely Mesozoic to Cenozoic in age depending on deposit. The black inclusions crystallized during the rock’s cooling and weathering history.
Uses & applications
Used for cabochons, beads, carvings, tumbled stones, and decorative objects; it has modest jewelry and collecting value rather than precious-gem status.
Geological facts
Despite its trade name, it is generally not true jasper, which is a microcrystalline quartz variety. The distinctive spots resemble a Dalmatian dog’s coat.
Field identification & locations
Identify it by the cream feldspathic groundmass and irregular black mineral spots; it is commonly associated with material from Mexico. A glassy surface, uniform painted spots, or bubbles would suggest imitation.
