mineral

Tumbled blue quartz (likely dumortierite quartz)

Quartz, SiO₂, colored blue by dumortierite inclusions

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous to waxy luster, translucent blue to blue-gray color, conchoidal fracture, and no cleavage; the rounded surface indicates tumbling and polishing. The appearance could also represent dyed quartz or blue calcite, which cannot be confirmed visually.

Identified September 2, 2026More mineral →

Explore Tumbled blue quartz (likely dumortierite quartz) in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids and igneous rocks; dumortierite-bearing quartz forms when aluminum-rich inclusions develop during metamorphism. Quartz is geologically widespread and ranges from Precambrian to modern formations.

Uses & applications

Used as a lapidary and decorative stone in cabochons, carvings, jewelry, and polished specimens; it has little industrial value in this small form.

Geological facts

Natural blue quartz is uncommon, while dyed quartz and blue calcite are frequently sold in the same tumbled form. A steel file or glass scratch test can help distinguish quartz, but may damage the specimen.

Field identification & locations

Common sources include Brazil, Madagascar, India, and the United States. Check for even dye concentration in cracks and a glass-scratching hardness; professional testing is needed for a confident identification.