Clinozoisite
Current inventory:  1 gem
 

  
Clinozoisite is named from being the monoCLINic dimorph of Zoisite.

Discovered in 1896;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Ca₂Al₃Si₃O₁₂(OH)

Calcium Aluminum Silicate Hydroxide

Molecular Weight:

454.36 gm

Composition:

Calcium

17.64 %

Ca

24.68 %

CaO

Aluminum

17.82 %

Al

33.66 %

Al₂O₃

Silicon

18.54 %

Si

39.67 %

SiO₂

Hydrogen

0.22 %

H

1.98 %

H₂O

Oxygen

45.78 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/C.23-10

Nickel-Strunz 10th Ed. ID:

9.BG.05a

9 : SILICATES (Germanates)
B : Sorosilicates
G : Sorosilicates with mixed SiO₄ and Si₂O₇ groups; cations in octahedral [6] and greater coordination

Related to:

Epidote Group. Clinozoisite-Epidote Series. Dimorphous with Zoisite. The Al₃ analogue of Epidote.

Members of Group:

Epidote Group: Allanite-(Ce), Allanite-(La), Allanite-(Y), Åskagenite-(Nd), Clinozoisite, Clinozoisite-(Sr), Dissakisite-(Ce), Dissakisite-(La), Dollaseite-(Ce), Epidote, Epidote-(Pb), Epidote-(Sr), Ferriallanite-(Ce), Khristovite-(Ce), Manganiandrosite-(Ce), Manganiandrosite-(La), Manganipiemontite-(Sr), Mukhinite, Piemontite, Piemontite-(Sr), Uedaite-(Ce), Unnamed (Ca-analogue of Manganiandrosite-(La)), Unnamed (La-analogue of Ferriallanite-(Ce)), Unnamed (Mg-analogue of Ferriallanite-(Ce)), Unnamed (Mn-analogue of Ferriallanite-(Ce)), Vanadoandrosite-(Ce), Zoisite

Varieties:

Chrome-Clinozoisite, Clinothulite

Synonyms:

Aluminium-Epidote, Clinoepidote, Fouquéite

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals prismatic, typically elongated and striated; commonly coarse to fine granular; also fibrous. Twinning: Lamellar, uncommon.

Twinning:

Lamellar on {100}, uncommon

Physical Properties

Cleavage:

Perfect on {001}

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Moh's Hardness:

6.5

Density:

3.21 - 3.38 (g/cm³)

Luminescence:

Not Fluorescent

Radioactivity:

Not Radioactive

Optical Properties

Color:

Colorless, pale Yellow to Golden Yellow, Yellowish Green, Green, Gray, Pink, Red; Colorless in thin section

Transparency:

Transparent to Translucent

Luster:

Vitreous (glassy)

Refractive Index:

1.670 - 1.735  Biaxial ( + )

Birefringence:

0.006 - 0.011

Dispersion:

r > v  or  r < v

Pleochroism:

None

Occurances

Geological Setting:

Typically in low- to medium-grade regionally metamorphosed igneous and sedimentary rocks, as well as in contact metamorphosed calcium-rich sediments; an alteration product of plagioclase feldspars (saussuritization).

Common Associations:

Amphiboles, Plagioclase, Quartz

Common Impurities:

Ti, Fe, Mn, Mg

Type Locality:

Gösleswand (Goslerwand), Ströden, Prägraten, Virgen valley, East Tyrol, Tyrol, Austria

Year Discovered:

1896

View mineral photos:

Clinozoisite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Clinozoisite is a rare member of the Epidote Group of minerals that includes Allanite, Clinozoisite, Epidote, Piemontite, Tanzanite, Thulite and Zoisite. Clinozoisite is found in several locations throughout the world but gem quality crystals are rare. Possibly the best current source is the Skardu District, Baltistan, Northern Areas, Pakistan. Crystals from this source are small and usually heavily included, but have beautiful olive green, greenish yellow to golden yellow colors. Gems are also usually small and moderately included.

Distribution: A widespread mineral. Typical occurrences for good crystals include: from Skardu District, Baltistan, Northern Areas, Pakistan. At the Goslarwand, near Prägraten, Tirol, Austria. From Vernirovice, Czech Republic. At Kälviä, Finland. From Arendal, Norway. At Camaderry Mountain, County Wicklow, Ireland. From Amborompotsy, Madagascar. At Sittampundi, Madras, India. In the USA, from the Belvidere Mountain quarries, Lowell, Orleans County, Vermont; in northern Spade Spring Canyon, Los Angeles County, California; in the Nightingale district, Pershing County, Nevada. In Mexico, from the Juarez district, Baja California, and at Alamos, Sonora. In Canada, from Timmins, Ontario.
 

  
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