Brucite/hydromagnesite Mg(OH)2. Hardness: 2.5. It is a single crystal with a thick plate shape, and the common one is a flake aggregate; Sometimes fibrous aggregates are called fibrous brucite or brucite asbestos.

​Brucite is a naturally occurring mineral composed primarily of magnesium hydroxide (Mg(OH)₂), and it is commonly found in metamorphic rocks. While it shares some similarities with asbestos minerals, such as its fibrous structure, it is not classified as an asbestos mineral.

One of the primary industrial uses of brucite is as a flame retardant. When heated, brucite decomposes into magnesium oxide and water vapor, both of which help to suppress flames. This property makes brucite a valuable additive in fire-resistant materials, including coatings, plastics, and textiles. It is widely used in industries such as construction, automotive, and electronics to improve fire safety.

One of the primary uses of brucite is in the production of flame retardants. When heated, brucite decomposes into magnesium oxide and water vapor, both of which act as a barrier to fire, making it a key ingredient in fire-resistant materials like coatings, plastics, and textiles. This property makes brucite especially valuable in construction materials and automotive parts, where fire safety is crucial.