Judging quality
Dumortierite is harder than sodalite and shows a fibrous rather than granular texture. Blue quartz colored by dumortierite inclusions is a common and attractive form.
Silicate
Dumortierite
Dense blue borosilicate, usually massive or as fibrous inclusions in quartz. Hard, deeply colored and often mistaken for sodalite or lapis.
Care
Hard and durable. Soap and water.
History & lore
Industrially used in high-grade porcelain because it fires to a pure white ceramic.
Cultural history, recorded as tradition rather than as medical or scientific claim.
Common questions about Dumortierite
- What is Dumortierite?
- Dense blue borosilicate, usually massive or as fibrous inclusions in quartz. Hard, deeply colored and often mistaken for sodalite or lapis.
- How hard is Dumortierite and what is it made of?
- Dumortierite is a Silicate-family mineral with the composition Al7BO3(SiO4)3O3. It crystallizes in the orthorhombic system and rates 7-8.5 on the Mohs hardness scale. It occurs in blue, violet.
- Where does Dumortierite come from?
- Notable localities for Dumortierite include Brazil, Madagascar, USA (Nevada), Namibia.
- How do you tell good Dumortierite from filler?
- Dumortierite is harder than sodalite and shows a fibrous rather than granular texture. Blue quartz colored by dumortierite inclusions is a common and attractive form.
- How do you care for Dumortierite?
- Hard and durable. Soap and water.
See it in person
Photographs only go so far
Both rooms are open six days a week, and there is always someone happy to pull pieces out of the case so you can compare them under the light.