Moganite

Moganite
Chemical arrangement of Moganite
General
Category	Silicate mineral
Formula (repeating unit)	SiO2
Strunz classification	4.DA.20
Dana classification	75.01.04.02
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	I2/a
Identification
Color	Grey
Crystal habit	Massive
Mohs scale hardness	6
Luster	Earthy, dull
Streak	White
Diaphaneity	Transparent
Optical properties	Biaxial
Refractive index	nα = 1.524 nγ = 1.531
References

Moganite is a oxide mineral with the chemical formula SiO₂ (silicon dioxide) that was discovered in 1984. It crystallises in the monoclinic crystal system. Moganite is considered a polymorph of quartz: it has the same chemical composition as quartz, but a different crystal structure.

In 1994, the International Mineralogical Association (IMA) had disapproved it as being a separate mineral because it was not clearly distinguishable from quartz. It has only recently (2007) been approved as a valid species by the CNMNC, the Commission on New Minerals, Nomenclature and Classification (part of the IMA).

This mineral has been mainly found in dry locales such as Gran Canaria and Lake Magadi. It has been reported from a variety of locations in Europe, India and the United States. It was named for the municipality of Mogán on Gran Canaria. Physically, it has a hardness of about 6, a dull luster and appears gray in color but transparent.