Magnesium oxide wallboard
Magnesium oxide, more commonly called magnesia, is a versatile mineral that when used as part of a cement mixture and cast into thin cement panels under proper curing procedures and practices can be used in residential and commercial building construction. Some versions are suitable for a wide range of general building uses and for applications that require fire resistance, mold and mildew control, as well as sound control applications and many other benefits. As an environmentally friendly building material, magnesia board has strength and resistance due to very strong bonds between magnesium and oxygen atoms that form  magnesium oxide crystals (with the chemical formula MgO). Magnesia boards are used in place of traditional gypsum drywall as wall and ceiling covering material and sheathing. It is also used in a number of other construction applications such as fascias, soffit, shaft-liner and area separation, wall sheathing, and as tile backing (backer board) or as substrates for coatings and insulated systems such as finish systems, EIFS, and some types of stucco. Magnesia cement board for building construction is available is various sizes and thickness. It is not a paperfaced material. It generally comes in a light gray, white or  beige color. Numerous versions and value of grades exist including smooth face, rough texture, utility, versatile grades as well as different densities and strengths for different applications and uses. Presently various magnesia cement boards are widely used in Asia as a primary construction material. Some versions have been designated as the ‘official’ construction specified material of the 2008 Summer Olympics and some versions are used extensively on the inside and outside of all the walls, fireproofing beams, and as the sub-floor sheathing in one of the world's tallest buildings, Taipei 101, located in Taipei, Taiwan. Magnesia cement is  manufactured in a number of areas around the world, primarily near areas where magnesia based ore (periclase) deposits are mined. Major deposits are found in China, Europe, and Canada. Magnesia ore deposits in the US are negligible. Estimates put the use of magnesia board products at around 8 million ft² in Asia alone. It is gaining popularity in the US, particularly near coastal regions. Purpose and use. Magnesia is widely used primarily as wallboard alternative to conventional gypsum-based drywall and plywoods. The magnesia boards can be scored and snapped, sawed, drilled, and fastened to wood or steel framing. Magnesia  boards are a good example of the advances made in construction materials to meet changes in building codes for safety and durability .