Commercial grade dumortierite is correctly known as dumortierite quartz. This is because the material is quartz that's heavily included with crystals of dumortierite.
The abundance of crystals within the quartz is the reason for the stone being opaque.
Dumortierite quartz tumbled stones are graded according to purity. Material included with crystals of dumortierite and other minerals are given a lower grade.
The additional mineral inclusions are identified through different colours and markings in the stone.
COPPER
