metamorphic

Dalmatian jasper

Spotted rhyolite (commercially called Dalmatian jasper), chiefly quartz and feldspar with black aegirine/arfvedsonite inclusions

AI-generated identification · may be incorrect

Polished/tumbled, cream to yellowish groundmass with rounded black spots; opaque, vitreous to waxy luster, fine-grained texture, Mohs hardness about 6–7, and no visible cleavage. The black spots are mineral inclusions rather than true leopard markings.

Identified September 6, 2026More metamorphic →

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Physical properties

Formation & geological history

Usually a silica-rich volcanic rock, commonly described as altered or devitrified rhyolite; formed from volcanic lava and later mineral alteration, generally in Cenozoic volcanic settings. Most commercial material comes from Mexico.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, and decorative objects; valued mainly as an ornamental lapidary material rather than for construction.

Geological facts

“Dalmatian jasper” is a trade name, not a strict mineralogical species or true jasper classification. Its distinctive spots commonly consist of dark sodium-rich amphibole or pyroxene-group minerals.

Field identification & locations

Identify by the cream groundmass, sharply contrasting rounded black inclusions, fine texture, and hardness; it typically lacks banding and visible quartz crystals. Test cautiously because polished surfaces can mask texture; common sources include Chihuahua, Mexico.