| Clinozoisite | |
| Category: | Sorosilicates Epidote group |
| Formula: | Ca2Al3(Si2O7)(SiO4)O(OH) |
| Imasymbol: | Czo[1] |
| Strunz: | 9.BG.05a |
| Dana: | 58.2.1a.4 |
| System: | Monoclinic |
| Class: | Prismatic (2/m) (same H-M symbol) |
| Symmetry: | P21/m |
| Unit Cell: | a = 8.879, b = 5.583 c = 10.155 [Å]; β = 115.50°; Z = 2 |
| Color: | Colorless, green, gray, light green, yellow green, pink |
| Habit: | Elongated primatic crystals, striated; granular to fibrous |
| Twinning: | Lamellar on uncommon |
| Cleavage: | Perfect on |
| Fracture: | Irregular/uneven |
| Tenacity: | Brittle |
| Mohs: | 6–7 |
| Luster: | Vitreous |
| Streak: | Grayish white |
| Diaphaneity: | Transparent to translucent |
| Gravity: | 3.3–3.4 |
| Opticalprop: | Biaxial (+) |
| Refractive: | nα = 1.706 – 1.724 nβ = 1.708 – 1.729 nγ = 1.712 – 1.735 |
| Birefringence: | δ = 0.006 – 0.011 |
| 2V: | 14 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]