Vaterite
Encyclopedia
Vaterite is a mineral, a polymorph
of calcium carbonate
. It was named after the German mineralogist Heinrich Vater. It is also known as mu-calcium carbonate (μ-CaCO3) and has a JCPDS number of 13-192. Vaterite, like aragonite, is a metastable phase of calcium carbonate at ambient conditions at the surface of the earth. As it is less stable than either calcite or aragonite, vaterite has a higher solubility
than either of these phases. Therefore, once vaterite is exposed to water
, it converts to calcite
(at low temperature) or aragonite
(at high temperature: ~60&bsp;°C). However, vaterite does occur naturally in mineral spring
s, organic tissue, gallstone
s, and urinary calculi. In those circumstances, some impurities (metal
ions or organic matter) may stabilize the vaterite and prevent its transformation into calcite
or aragonite
. Vaterite is usually colorless, its shape is spherical, and its diameter is small, ranging from 0.05 to 5 μm.
Vaterite can be produced as the first mineral deposits repairing natural or experimentally induced shell damage in some aragonite-shelled molluscs (e.g., gastropods). Subsequent shell deposition occurs as aragonite.
Vaterite belongs to the hexagonal crystal system
, whereas calcite is trigonal and aragonite is orthorhombic.
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...
of calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
. It was named after the German mineralogist Heinrich Vater. It is also known as mu-calcium carbonate (μ-CaCO3) and has a JCPDS number of 13-192. Vaterite, like aragonite, is a metastable phase of calcium carbonate at ambient conditions at the surface of the earth. As it is less stable than either calcite or aragonite, vaterite has a higher solubility
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
than either of these phases. Therefore, once vaterite is exposed to water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
, it converts to calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
(at low temperature) or aragonite
Aragonite
Aragonite is a carbonate mineral, one of the two common, naturally occurring, crystal forms of calcium carbonate, CaCO3...
(at high temperature: ~60&bsp;°C). However, vaterite does occur naturally in mineral spring
Mineral spring
Mineral springs are naturally occurring springs that produce water containing minerals, or other dissolved substances, that alter its taste or give it a purported therapeutic value...
s, organic tissue, gallstone
Gallstone
A gallstone is a crystalline concretion formed within the gallbladder by accretion of bile components. These calculi are formed in the gallbladder, but may pass distally into other parts of the biliary tract such as the cystic duct, common bile duct, pancreatic duct, or the ampulla of...
s, and urinary calculi. In those circumstances, some impurities (metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
ions or organic matter) may stabilize the vaterite and prevent its transformation into calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
or aragonite
Aragonite
Aragonite is a carbonate mineral, one of the two common, naturally occurring, crystal forms of calcium carbonate, CaCO3...
. Vaterite is usually colorless, its shape is spherical, and its diameter is small, ranging from 0.05 to 5 μm.
Vaterite can be produced as the first mineral deposits repairing natural or experimentally induced shell damage in some aragonite-shelled molluscs (e.g., gastropods). Subsequent shell deposition occurs as aragonite.
Vaterite belongs to the hexagonal crystal system
Hexagonal crystal system
In crystallography, the hexagonal crystal system is one of the 7 crystal systems, the hexagonal lattice system is one of the 7 lattice systems, and the hexagonal crystal family is one of the 6 crystal families...
, whereas calcite is trigonal and aragonite is orthorhombic.
See also
- Monohydrocalcite, CaCO3·H2OMonohydrocalciteMonohydrocalcite is a mineral that is a hydrous form of calcium carbonate, CaCO3·H2O. It was formerly also known by the name hydrocalcite, which is now discredited by the IMA. It is a trigonal mineral which is white when pure...
- Ikaite, CaCO3·6H2OIkaiteIkaite is the mineral name for the hexahydrate of calcium carbonate, CaCO3·6H2O. It is only found in a metastable state, and decomposes rapidly once removed from near-freezing water. It is more commonly known through its pseudomorphs.-Distribution:...
- List of minerals
- List of minerals named after people