Magnesium rich minerals often become talc through hydrothermal alteration, so talcum is often a mineral illusion of olivine, pyroxene, hornblende and tremolite. Talc is a common silicate mineral. It is very soft and has a smooth handle. Ten minerals have been selected to represent ten hardness levels, called the Moss hardness, in which the first (i.e. the softest) is talc. Soft talc can replace white chalk with white marks. Talc is usually lump, leaf, fibrous or radial, white, gray-white color, and will contain other impurities and with a variety of colors. Talc is a talc talc mineral talc, mainly containing hydrated magnesium silicate. The crystal structure of talc belongs to monoclinic system, which is formed by the combination of magnesium and silicification in hot water solution and rock. Talc is a type of hydrotherm alteration mineral. After alteration, magnesite ore will becomes to talc, therefore talc is often seemed like olivine, enstatite, hornblende, tremolite. Talc is normal silicate minerals, and it is soft and creamy. Talc is the softest ore, Moh's hardness 1. Soft talc could be used to draw like chalk does. Talc exists in bulk, blade, threadiness or radial shape present white or gray, talc could present different color as the impurity contained, and hydrated magnesium silicate is the main element.