Boracite

Boracite

Found in Boulby mine, Boulby, Cleveland.

Boracite is an unusual magnesium borate mineral.  It occurs as blue green, colorless, gray, yellow to white crystals in the orthorhombic - pyramidal crystal system.

Boracite also shows pseudo-isometric cubical and octahedral forms. These are thought to be the result of transition from an unstable high temperature isometric form on cooling.



Physical properties of Boracite:

Chemical composition: Mg3B7O13Cl

Hardness: 7 - 7.5

Specific gravity: 2.9