The Gemstone Dumortierite

Round Dumortierite Cabochon

Dumortierite is a minor blue gemstone that usually forms as inclusions in Quartz. Its most common color is blue or grayish-blue, though pink and purple colors are also known. Dumortierite's durability, combined with a high hardness, would make this an ideal gemstone, but the lack of transparency and often dull luster limit its use. 


? Blue, Pink, Purple


? 7

Chemical Formula

? AlAl6O3BSi3O18

Mineral Class

? Dumortierite

Additional Properties

Crystal System
? Orthorhombic
Refractive Index
? 1.67 - 1.72
Double Refraction
? 0.01 - 0.04
? Translucent to opaque
? 3.3 - 3.4
? Vitreous, silky
Cleavage ? 2,1;3,1

All About

Pure Dumortierite gemstones are rarely encountered. Most lapidary-grade Dumortierite is dense blue inclusions of Dumortierite within Quartz. These gemstones are often called by the confusing term "Dumortierite Quartz", or may even be called "Blue Quartz". The inclusions can be present throughout the Quartz, or in splotches or zones, resulting in light and dark blue color zones.

The properties listed above are inherent to pure Dumortierite. However, since most Dumortierite gemstones are actually Quartz with Dumortierite inclusions, the properties listed under Quartz are the more accurate gemstone reference.


? Dumortierite is a minor gemstone used mostly in cabochons and lapidary carvings.

Other Names




Treatments & Enhancements

? Dumortierite gemstones are natural and not treated or enhanced.

Dumortierite Sources

? Dumortierite sources include Brazil, Peru, Madagascar, Namibia, Austria, and the U.S. (California).

Similar Gemstones

? Dumortierite has a greater hardness than Lapis Lazuli and Sodalite, and usually lacks the white veins often present in these two gemstones.

Dumortierite Photos


Dumortierite in the Rough Photos



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