Hydrotalcite is a layered double hydroxide of general formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 (Mg₆Al₂(CO₃)(OH)₁₆·4(H₂O) whose name is derived from its resemblance with talc

Talc

Talc is a mineral composed of hydrated magnesium silicate with the chemical formula H2Mg34 or Mg3Si4O102. In loose form, it is the widely-used substance known as talcum powder. It occurs as foliated to fibrous masses, its crystals being so rare as to be almost unknown...

 and its high water content. It is dimorphous

Polymorphism (materials science)

Polymorphism in materials science is the ability of a solid material to exist in more than one form or crystal structure. Polymorphism can potentially be found in any crystalline material including polymers, minerals, and metals, and is related to allotropy, which refers to chemical elements...

 with and often intermixed with manasseite.

It was first described in 1842 for an occurrence in a serpentine - magnesite

Magnesite

Magnesite is magnesium carbonate, MgCO3. Iron substitutes for magnesium with a complete solution series with siderite, FeCO3. Calcium, manganese, cobalt, and nickel may also occur in small amounts...

 deposit in Snarum, Modum

Modum

Modum is a municipality in Buskerud county, Norway. It is part of the traditional region of Hallingdal. The administrative centre of the municipality is the town of Vikersund. The municipality of Modum was established on 1 January 1838 .The area has a long tradition of skiing with several famous...

, Buskerud

Buskerud

is a county in Norway, bordering Akershus, Oslo, Oppland, Sogn og Fjordane, Hordaland, Telemark, and Vestfold. The county administration is located in Drammen.-Geography:...

, Norway

Norway

Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

. In occurs as an alteration mineral in serpentinite

Serpentinite

Serpentinite is a rock composed of one or more serpentine group minerals. Minerals in this group are formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from the Earth's mantle...

 in association with manasseite, serpentine and dolomite

Dolomite

Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....

.

See also

• Brucite
  Brucite
  Brucite is the mineral form of magnesium hydroxide, with the chemical formula Mg2. It is a common alteration product of periclase in marble; a low-temperature hydrothermal vein mineral in metamorphosed limestones and chlorite schists; and formed during serpentinization of dunites...
  
  , Mg(OH)₂
• Fougerite
  Fougerite
  Fougerite is a recently discovered representative of clay minerals, chemically and structurally related to so-called green rust, hydrotalcite-like minerals and other layered double hydroxides. The formula of the mineral is complex due to structural variabilities, as is for green rust, thus...
  
  
• Layered double hydroxide
• Magnesium hydroxide
  Magnesium hydroxide
  Magnesium hydroxide is an inorganic compound with the chemical formula Mg2. As a suspension in water, it is often called milk of magnesia because of its milk-like appearance. The solid mineral form of magnesium hydroxide is known as brucite....