Akaogiite (
IMA symbol
A symbol is a mark, Sign (semiotics), sign, or word that indicates, signifies, or is understood as representing an idea, physical object, object, or wikt:relationship, relationship. Symbols allow people to go beyond what is known or seen by cr ...
Aka
) is an exceedingly rare mineral, one of the natural forms of
titanium dioxide
Titanium dioxide, also known as titanium(IV) oxide or titania , is the inorganic compound derived from titanium with the chemical formula . When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or Colour Index Internationa ...
(TiO
2). It is a high-pressure
polymorph of TiO
2, along with
anatase
Anatase is a metastable mineral form of titanium dioxide (TiO2) with a Tetragonal crystal system, tetragonal crystal structure. Although colorless or white when pure, anatase in nature is usually a black solid due to impurities. Three other Pol ...
,
brookite
Brookite is the Orthorhombic crystal system, orthorhombic variant of titanium dioxide (TiO2), which occurs in four known natural Polymorphism (materials science), polymorphic forms (minerals with the same composition but different structure). The ...
and another high-pressure phase called "TiO
2 II".
Rutile
Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite.
Rutile has one of the highest refractive indices at vis ...
is the stable polymorph of TiO
2, most commonly found at standard temperatures and pressures.
Akaogiite can be found at the
Nördlinger Ries
The Nördlinger Ries is an impact crater and large circular depression in western Bavaria and eastern Baden-Württemberg. It is located north of the Danube in the district of Donau-Ries. The city of Nördlingen is located within the depression ...
Crater, a
meteor crater in Germany, where the extreme pressure during the impact allowed its formation.
References
Oxide minerals
Titanium minerals
Monoclinic minerals
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