Humite

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Humite
Humite-155029.jpg
Humite specimen, Italy
General
Category Nesosilicates
Formula
(repeating unit)
(Mg,Fe)7(SiO4)3(F,OH)2.
Strunz classification 09.AF.50
Crystal symmetry Orthorhombic dipyramidal H–M Symbol (2/m 2/m 2/m)
Unit cell a = 10.24 Å, b = 20.72 Å, c = 4.73 Å; Z = 4
Identification
Color White, yellow, dark orange, brown
Crystal system Orthorhombic
Cleavage Poor
Fracture Uneven to subconchoidal
Tenacity Brittle
Mohs scale hardness 6-6.5
Luster Vitreous
Streak White
Diaphaneity Transparent
Specific gravity 3.20 – 3.32
Optical properties Biaxial (+)
Refractive index nα =1.607-1.643, nβ=1.619-1.653, nγ=1.639-1.675
Birefringence 0.0320
2V angle Calculated = 70-78°, measured = 68-81°
Dispersion Weak, r > v
References [1][2][3]
For the eponymous group of minerals, see Humite (mineral group).

Humite is a mineral found in the volcanically ejected masses of Vesuvius. It was first described in 1813 and named for Abraham Hume (1749–1838).[4]

See also[edit]

References[edit]

  1. ^ Handbook of Mineralogy
  2. ^ Webmineral data
  3. ^ Mindat w/ locations
  4. ^ Deer, W.; Howie, R.; Zussman, J. (1997). Rock-forming Minerals: Volume 1A, Second Edition, Orthosilicates. Bath, UK: The Geological Society. ISBN 1-897799-88-8. 

External links[edit]

Media related to Humite at Wikimedia Commons