Clinozoisite

sorosilicate

metamorphic

Formula: Ca2Al3[Si2O7][SiO4]O(OH)
Sorosilicate (Si2O7 groups) epidote group
Specific gravity:
Hardness: 7
Streak: Greyish white
Colour: Colourless, green, grey, light green, yellow-green, pink
Solubility: Insoluble in water, nitric and sulphuric acid; soluble in hydrochloric acid
Environments:

Metamorphic environments

Clinozoisite is a mineral of the amphibolite facies.

Alteration

calcium-iron amphibole and anorthite to garnet (grossular and almandine), clinozoisite and quartz
Ca2Fe3Si8O22(OH)2 + 6Ca(Al2Si2O8) ⇌ 4/3Ca3Al2(SiO4)3 + 5/3Fe3Al2(SiO4)3 + 2Ca2Al3[SiO7][SiO4]O(OH) + 5SiO2
(MM 48.206)

amphibole, clinozoisite, chlorite, albite, ilmenite and quartz to garnet, omphacite, rutile and H2O
NaCa2(Fe2Mg3)(AlSi7)O22(OH)2 + 2Ca2Al3[Si2o7][SiO4]O(OH) + Mg5Al(AlSi3O10)(OH)8 + 3NaAlSi3O8 + 4Fe2+Ti4+O3 + 3SiO2 → 2(CaMg2Fe3)Al4(SiO4)6 + 4NaCaMgAl(Si2O6)2 + 4TiO2 + 6H2O
In low-grade rocks relatively poor in calcite the garnet - omphacite association may be developed by the above reaction.

lawsonite and jadeite to clinozoisite, paragonite, quartz and H2O
4CaAl2(Si2O7)(OH)2.H2 + NaAlSi2O6 ⇌ 2Ca2Al3[Si2O7][SiO4]O(OH) + NaAl2(Si3Al)O10(OH)2 + SiO2 +6H2
Clinozoisite and paragonite may have been derived from lawsonite by the above reaction.

meionite (scapolite series) and H2O to clinozoisite and CO2
Ca4Al6O24(CO3) + H2O ⇌ 2Ca2Al3[Si2O7][SiO4]O(OH) + CO2

Common impurities: Ti,Fe,Mn,Mg

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