Clinozoisite

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Clinozoisite
Clinozoisite, Amphibole Group - Mount Belvidere Quarries, Vermont, USA.jpg
Clinozoisite
General
CategorySorosilicates
Epidote group
Formula
(repeating unit)
Ca2Al3(Si2O7)(SiO4)O(OH)
Strunz classification9.BG.05a
Dana classification58.2.1a.4
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/m
Unit cella = 8.879, b = 5.583
c = 10.155 [Å]; β = 115.50°; Z = 2
Identification
ColorColorless, green, gray, light green, yellow green
Crystal habitElongated primatic crystals, striated; granular to fibrous
TwinningLamellar on {100} uncommon
CleavagePerfect on {001}
FractureIrregular/uneven
TenacityBrittle
Mohs scale hardness6-7
LusterVitreous
StreakGrayish white
DiaphaneityTransparent to translucent
Specific gravity3.3 - 3.4
Optical propertiesBiaxial (+)
Refractive indexnα = 1.706 - 1.724 nβ = 1.708 - 1.729 nγ = 1.712 - 1.735
Birefringenceδ = 0.006 - 0.011
2V angle14 to 90° measured
References[1][2][3]

Clinozoisite is a complex calcium aluminium sorosilicate mineral with formula: Ca2Al3(Si2O7)(SiO4)O(OH). It forms a continuous solid solution series with epidote by substitution of iron(III) in the aluminium (m3 site) and is also called aluminium epidote.[1]

Clinothulite is a manganese bearing variety with a pinkish hue due to substitution of Mn(III) in the aluminium site.[4]

It was originally discovered in 1896 in East Tyrol, Austria, and is so-named because of its resemblance to zoisite and its monoclinic crystal structure.[1]

It occurs in rocks which have undergone low to medium grade regional metamorphism and in contact metamorphism of high calcium sedimentary rocks. It also occurs in saussurite alteration of plagioclase.[2]

Jadeite bearing pyroxene minerals have suggested Clinozoisite and paragonite are associated and derived from lawsonite releasing Quartz and water via the following reaction:[5]

References[edit]

  1. ^ a b c Clinozoisite on Mindat.org
  2. ^ a b Clinozoisite in the Handbook of Mineralogy
  3. ^ Clinozoisite data on Webmineral
  4. ^ Clinothulite on Mindat
  5. ^ Deer, William A. (1997). Single-chain Silicates, Volume 2A. Geological Society of London. p. 477.
  • Nesse, William D., "Introduction to Mineralogy," (c)2000 Oxford University Press ISBN 0-19-510691-1