World Library  
Flag as Inappropriate
Email this Article

Halotrichite

Article Id: WHEBN0001957874
Reproduction Date:

Title: Halotrichite  
Author: World Heritage Encyclopedia
Language: English
Subject: Sulfate minerals, Mojave, California, Monoclinic crystal system, Alunogen, Copiapite
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Halotrichite

Halotrichite
A sample of Halotrichite
General
Category Sulfate minerals
Formula
(repeating unit)
FeAl2(SO4)4·22H2O.
Strunz classification 07.CB.85
Crystal symmetry Monoclinic sphenoidal
H-M symbol: (2)
Space group: P 2
Unit cell a = 20.51 Å, b = 24.29 Å, c = 6.18 Å; β = 100.99°; Z=4
Identification
Color Colorless to white, yellowish, greenish
Crystal habit Acicular to asbestiform clusters, incrustations and efflorescences
Crystal system Monoclinic
Cleavage Poor on {010}
Fracture Conchoidal
Tenacity Brittle
Mohs scale hardness 1.5 - 2
Luster Vitreous
Diaphaneity Transparent, translucent
Specific gravity 1.89
Optical properties Biaxial (-)
Refractive index nα = 1.480 nβ = 1.486 nγ = 1.490
Birefringence δ = 0.010
2V angle Measured: 35°
Solubility Soluble in water
Other characteristics Astringent taste
References [1][2][3]

Halotrichite, also known as feather alum, is a highly hydrated sulfate of aluminium and iron. Its chemical formula is FeAl2(SO4)4·22H2O. It forms fibrous monoclinic crystals. The crystals are water-soluble.

It is formed by the weathering and decomposition of pyrite commonly near or in volcanic vents. Occurrences include the Atacama Desert, Chile, Dresden, Saxony, Germany, San Juan County, Utah, Iceland, and Mont Saint-Hilaire, Canada.

The name is from Latin: halotrichum for salt hair.[3]

Halotrichite from California
Halotrichite from the abandoned Golden Queen mine on Soledad Mountain south of Mojave, California

References

  1. ^ Handbook of Mineralogy
  2. ^ Halotrichite on Mindat.org
  3. ^ a b Halotrichite data on Webmineral
  • Saint-Hilaire
  • Mineral Atlas


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 USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov 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.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.