Clinozoisite

Clinozoisite
Clinozoisite
General
CategorySorosilicates
Epidote group
Formula
(repeating unit)		Ca2Al3(Si2O7)(SiO4)O(OH)
IMA symbolCzo[1]
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, pink
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[2][3][4]

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.[2]

Clinothulite is a manganese bearing variety with a pinkish hue due to substitution of Mn(III) in the aluminium site.[5]

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.[2]

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.[3]

Jadeite bearing pyroxene minerals have suggested clinozoisite and paragonite are associated and derived from lawsonite releasing quartz and water via the following reaction:[6]

References

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b c Clinozoisite on Mindat.org
  3. ^ a b "Clinozoisite in the Handbook of Mineralogy" (PDF). Archived from the original (PDF) on 2015-09-24. Retrieved 2014-03-24.
  4. ^ Clinozoisite data on Webmineral
  5. ^ Clinothulite on Mindat
  6. ^ 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


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