Colemanite

The colemanite is a boron mineral, named in honor of William Coleman, founder of an important California boraciferous industry and owner of the mine where the colemanite was first discovered.

Colemanite has an evaporitic genesis and is generally formed in arid environments. It is chemically stable and it can either be colorless, or can be found in a range of colors including white, yellowish-white, gray, and gray-white. It has a transparent to translucent appearance, perfect cleavage, white streak, and vitreous luster. It is fluorescent in nature, and its fractures appear brittle.

I.MA.F. sells ground colemanite for the rubber industry. Colemanite is used in the production of rubber sleeves and protective spirals and in the production of slabs for waterproofing roots because it increased the elastic modulus and especially the breaking strain while it decreased the yield stress and the yield strain of the material.