Dumortierite (2) Raw Minerals Stones Rocks Collecting

Description

Origin : Brazil

Dumortierite 20-30 gr - cm 2,5-4,5 Raw Minerals Stones Rocks for Collection.
Boron and Aluminum Silicate.

Dumortierite is a variously colored fibrous aluminum borosilicate. It was named in honor of the French paleontologist Eugène Dumortier.
Dumortierite forms typical compact fibrous aggregates composed of thin prismatic crystals. The crystals are glassy with variable colors: blue, red, brown, green. More rarely violet or pink. The coloring depends on the substitution of the aluminum atoms with iron atoms or other trivalent metals.
It forms in aluminum-rich metamorphic rocks at high temperatures after slow cooling. It is found in masses of mining interest in Nevada, California and Arizona. In Europe it is present in France. It is also found in Madagascar and Brazil. In Italy it has been reported in the pegmatites of Sondalo in Lombardy.
Dumortierite is hard, heavy, well flaky. It is used in the manufacture of quality porcelain and for the preparation of aluminous refractories.
Dumortierite is often confused with azure quartz or blue quartz. It actually has nothing to do with quartz. The error derives only from the fact that sometimes the blue color of some massive quartz is due precisely to inclusions of dumortierite. However, quartz can take on the same color even for inclusions of different materials. Furthermore, dumortierite may appear unassociated with quartz.
Submicroscopic inclusions of dumortierite provide the typical rose quartz coloration.