This is a natural material that is thought to have formed by the metamorphism of coal seams. The impurities are generally clays. This material has no visible crystalline structure except for flat surface cleavage.
Used in friction materials, metallurgy, pencils, refractories, coatings, lubricants, rubber compounds, paints
Available in a wide range of sizes from 3/4" to 15 micron powders.