Piemontite 3.09 ct.

Piemontite

Piemontite is a sorosilicate mineral in the monoclinic crystal system with the chemical formula Ca2(Al,Mn3+,Fe3+)3(SiO4)(Si2O7)O(OH). It is a member of the epidote group.

Red to reddish-brown or red-black in colour, Piemontite has a red streak and a vitreous lustre.

The type locality is the Praborna Mine, in Saint-Marcel, Aosta Valley, Italy.

It occurs metamorphic rocks of the greenschist to amphibolite metamorphic facies and in low-temperature hydrothermal veins in altered volcanic rocks. It also occurs in metasomatized deposits of manganese ore. Associated minerals include: epidote, tremolite, glaucophane, orthoclase, quartz and calcite.The hardness is 6-6.5.

Size: 6.9x10.4x5.1 mm.

Weight: 3.09 ct.

CODE#6831