Humite

Humite specimen, Italy

General
Category| Nesosilicates
Formula
(repeating unit)| (Mg,Fe)7(SiO4)3(F,OH)2.
Strunz classification| 9.AF.50
Crystal system| Orthorhombic
Crystal class| Dipyramidal (mmm)
H–M Symbol: (2/m 2/m 2/m)
Space group| Pbnm
Unit cell| a = 10.24, b = 20.72
c = 4.73 [Å]; Z = 4
Identification
Color| White, yellow, dark orange, brown
Cleavage| Poor
Fracture| Uneven to subconchoidal
Tenacity| Brittle
Mohs scale hardness| 6–6.5
|re|er}}| 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]

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).[5]

## See also

* Alleghanyite
* Chondrodite
* Clinohumite
* Jerrygibbsite

## References

1. ↑ Handbook of Mineralogy
2. ↑ Webmineral data
3. ↑ Mindat w/ locations
4. ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode: 2021MinM...85..291W.
5. ↑ 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

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Humite. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Humite&oldid=439208"