Chemical Formula AlAl6O3BSi3O18
Color Blue, Pink, Purple
Hardness 7
Crystal System Orthorhombic
Refractive Index 1.67 – 1.72
SG 3.3 – 3.4
Transparency Translucent to opaque
Double Refraction 0.01 – 0.04
Luster Vitreous, silky
Cleavage 2,1;3,1
Mineral Class Dumortierite

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.


Blue Denim Stone
Bahia Blue Quartz – Synonym of Dumortierite Quartz
Blue Moon Quartz – Synonym of Dumortierite Quartz
Dumortierite Quartz – Dumortierite formed as dense inclusions within Quartz, creating a natural blue gemstone form of Quartz.Dumortierite gemstones are natural and not treated or enhanced.Dumortierite sources include Brazil, Peru, Madagascar, Namibia, Austria, and the U.S. (California).Dumortierite has a greater hardness than Lapis Lazuli and Sodalite, and usually lacks the white veins often present in these two gemstones. Fluorite makes a beautiful gemstone that comes in all colors, and can often be multicolored with two or more contrasting color within the same gemstone. Multicolored Fluorite gemstones often show banding patterns. Large and flawless crystals are fairly common, and these can produce very large and totally clear gemstones. However, due to Fluorite’s very low hardness and perfect cleavage, it cannot be used as a mainstream gemstone, and it is generally cut specifically for specialty collectors.
Dumortierite SOURCES

Comments are closed