Rock Identifier
Polished purple-gray stone, possibly lepidolite or purple jasper (Lepidolite (K(Li,Al)₃(Si,Al)₄O₁₀(F,OH)₂) or quartz-rich jasper) — mineral
mineral

Polished purple-gray stone, possibly lepidolite or purple jasper

Lepidolite (K(Li,Al)₃(Si,Al)₄O₁₀(F,OH)₂) or quartz-rich jasper

AI-generated identification · may be incorrect

The rounded, polished specimen appears lavender-gray with a dull to waxy luster and an embedded darker vein or cavity. Lepidolite has Mohs hardness 2.5–3.5 and basal cleavage; jasper is quartz-rich, about 6.5–7, with no obvious cleavage. The image alone cannot reliably distinguish them.

Identified More mineral
Explore Polished purple-gray stone, possibly lepidolite or purple jasper in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

Physical properties

The rounded, polished specimen appears lavender-gray with a dull to waxy luster and an embedded darker vein or cavity. Lepidolite has Mohs hardness 2.5–3.5 and basal cleavage; jasper is quartz-rich, about 6.5–7, with no obvious cleavage. The image alone cannot reliably distinguish them.

Formation & geological history

Lepidolite forms in lithium-rich granite pegmatites during late-stage crystallization; jasper forms when silica-rich fluids replace or cement sedimentary or volcanic material. Precise age and locality are unavailable from the photograph.

Uses & applications

Lepidolite is collected for its color and lithium-bearing mica; jasper is used for cabochons, carvings, tumbled stones, and ornamental objects. This appears primarily decorative or lapidary.

Geological facts

Purple coloration may result from manganese, iron, mica, or other trace elements. A hardness test, streak, and close examination of mica-like cleavage would help separate lepidolite from jasper.

Field identification & locations

Common sources include Brazil, Madagascar, and the western United States for lepidolite, and worldwide volcanic or sedimentary terrains for jasper. Avoid destructive testing if it is a valued polished piece.