Category Phyllosilicate
(repeating unit)
Strunz classification 09.EA.20
Unit cell a = 7.25 Å, b = 7.25 Å, c = 15.69 Å; β = 96.8°; Z=2
Color White
Crystal habit Minute platy crystals; spherulitic aggregates; powdery
Crystal system Monoclinic
Tenacity Puttylike
Mohs scale hardness 2
Luster Vitreous - dull
Streak White
Diaphaneity Translucent to opaque
Specific gravity 2.25 calculated
Optical properties Biaxial
Refractive index nα = 1.470
Ultraviolet fluorescence Yellow-white under both long and short wave
References [1][2][3]

Magadiite is a hydrous sodium silicate mineral (NaSi7O13(OH)3·4(H2O)) which precipitates from alkali brines as an evaporite phase. It forms as soft (Mohs hardness of 2) white powdery monoclinic crystal masses.[1][2] The mineral is unstable and decomposes during diagenesis leaving a distinctive variety of chert (Magadi-type chert).[4]

The mineral was first described by Hans P. Eugster in 1967 for an occurrence in Lake Magadi, Olduvai Gorge, Kenya.[2][4] It is also reported from alkalic intrusive syenites as in Mont Saint-Hilaire, Canada.[1]


This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.