Magnesite is a carbonate of magnesium, one of the sources of magnesium compounds, and can be divided into crystalline magnesite and amorphous magnesite.

In addition, magnesium compounds can also be extracted from dolomite, forsterite, brucite, magnesium-containing salt lake water, and even seawater.

Magnesite often contains iron, which results from iron or manganese replacing magnesium. It is white or light gray, shiny, with a hardness of 3.5-4.5 and a specific gravity of 2.95-3.1. It is mainly produced in Zimbabwe, Brazil, Australia and China. Its application value is mainly to produce materials with a high magnesium oxide content, which has good refractory and adhesion. In addition, it is also the main raw material used to refine magnesium metal.