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It occurs in nature also in boracite, datolite, tourmaline, and some other minerals.

In boracite there are four uniterminal triad axes, and the faces of the two tetrahedra perpendicular to them will bear opposite charges.

Tetrahedrite, blende, diamond, boracite and pharmacosiderite are substances which crystallize in this class.

For example, he observed that crystals of leucite and boracite, which are cubic in external form, are always doubly refracting and optically biaxial, but with a complex internal structure; and that cubic crystals of garnet and analcite sometimes exhibit the same phenomena.

It may also be obtained by the decomposition of boracite with hot hydrochloric acid.