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Not to be confused with Morganite.
Category Silicate mineral
(repeating unit)
Strunz classification 04.DA.20
Dana classification
Colour Grey
Crystal habit Massive
Crystal system Monoclinic - prismatic (2/m)
Mohs scale hardness 6
Luster Earthy, dull
Streak White
Diaphaneity Transparent
Optical properties Biaxial
Refractive index nα = 1.524 nγ = 1.531
References [1][2]

Moganite is a silicate mineral with the chemical formula SiO2 (silicon dioxide) that was discovered in 1984.[1] 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.[2]

In 1994, the International Mineralogical Association (IMA) had disapproved it as being a separate species because it was not clearly distinguishable from quartz.[3] It has only recently been approved as a valid species by the CNMNC, the Commission on New Minerals, Nomenclature and Classification (part of the IMA).[4]

Chemical arrangement of Moganite

This mineral is “virtually indistinguishable” from chalcedony which is made up of both moganite and quartz. It has been mainly found in dry locales such as Gran Canaria and Lake Magadi.[5] It has been reported from a variety of locations in Europe, India and the United States.[1] It was named for the municipality of Mogán on Gran Canaria.[2] Physically, it has a hardness of about 6, a dull luster and appears gray in color but transparent.


  1. ^ a b c Ralph, Jolyon, and Ida Ralph. "Moganite: Moganite Mineral Information and Data." MinDat. 2007. Aug. 2007 <>.
  2. ^ a b c Webmineral data
  3. ^ Origlieri, Marcus. "Moganite: a New Mineral -- Not!" Lithosphere (1994). Aug. 2007 <>.
  4. ^ Nickel, Ernest H., and Monte C. Nichols. "IMA/CNMNC List of Mineral Names." Materials Data. June 2007. Aug. 2007[dead link]
  5. ^ Heaney, Peter J., and Jeffrey E. Post. "The Widespread Distribution of a Novel Silica Polymorph in Microcrystalline Quartz Varieties." Science ns 255 (1992): 441-443. JSTOR. Aug. 2007. Keyword: moganite.

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