Vesuvianite
| Vesuvianite | |
|---|---|
 Vesuvianite from the Jeffrey Mine inAsbestos, Quebec | |
| General | |
| Category | Sorosilicate |
| Formula (repeating unit) | Ca10(Mg, Fe)2Al4(SiO4)5(Si2O7)2(OH,F)4 |
| IMA symbol | Ves[1] |
| Strunz classification | 9.BG.35 |
| Crystal system | Tetragonal |
| Crystal class | Ditetragonal dipyramidal (4/mmm) H-M symbol:(4/m 2/m 2/m) |
| Space group | P4/nnc |
| Unit cell | a= 15.52 Å,c= 11.82 Å Z = 2 |
| Identification | |
| Color | Yellow, green, brown; colorless to white, brown-black, light green, emerald green, violet, blue-green to blue, pink, purple, red, black, commonly zoned |
| Crystal habit | Short pyramidal to long prismatic crystals common, massive to columnar |
| Twinning | Fine twin domains observed |
| Cleavage | Poor on {110} and {100} very poor on {001} |
| Fracture | Sub conchoidal to irregular |
| Tenacity | Brittle |
| Mohs scalehardness | 6–7 |
| Luster | Vitreous to resinous |
| Streak | White |
| Diaphaneity | Subtransparent to translucent |
| Specific gravity | 3.32–3.43 |
| Optical properties | Uniaxial (−) |
| Refractive index | nω= 1.703–1.752 nε= 1.700–1.746 |
| Birefringence | 0.004–0.006 |
| Pleochroism | slight in colored varieties |
| Solubility | Vesuvianite is virtually insoluble in acids |
| Other characteristics | striated lengthwise |
| References | [2][3][4] |
Vesuvianite,also known asidocrase,is a green, brown, yellow, or bluesilicate mineral.Vesuvianite occurs astetragonalcrystalsinskarndeposits andlimestonesthat have been subjected to contactmetamorphism.[3]It was first discovered within included blocks or adjacent tolavasonMount Vesuvius,hence its name. Attractive-looking crystals are sometimes cut as gemstones. Localities which have yielded fine crystallized specimens include Mount Vesuvius and the Ala Valley near Turin,Piedmont.[5]
Thespecific gravityis 3.4 and theMohs hardnessis6+1⁄2.The name "vesuvianite" was given byAbraham Gottlob Wernerin 1795, because fine crystals of the mineral are found at Vesuvius; these are brown in color and occur in the ejected limestone blocks ofMonte Somma.Several other names were applied to this species, one of which, "idocrase" byRené Just Haüyin 1796, is now in common use.[5]
A sky bluish variety known ascyprinehas been reported fromFranklin, New Jerseyand other locations; the blue is due to impurities of copper in a complex calcium aluminum sorosilicate.Californiteis a name sometimes used forjade-like vesuvianite, also known asCalifornia jade,American jadeorVesuvianite jade.Xanthiteis amanganeserich variety.Wiluiteis an optically positive variety from Wilui,Siberia.Idocrase is an older synonym sometimes used forgemstone-quality vesuvianite. Also,VessoniteandVassoliteare variant spellings commonly encountered in the gem trade.
References
[edit]- ^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.S2CID235729616.
- ^Mindat with location data
- ^abHandbook of Mineralogy
- ^https:// mineralienatlas.de/lexikon/index.php/MineralData?mineral=VesuvianiteMineralienatlas
- ^abOne or more of the preceding sentences incorporates text from a publication now in thepublic domain:Spencer, Leonard James(1911). "Vesuvianite".InChisholm, Hugh(ed.).Encyclopædia Britannica.Vol. 27 (11th ed.). Cambridge University Press. p. 1063.
Additional sources
[edit]- Deere, W. A.; et al. (1962).Rock Forming Minerals.Vol. 1. pp. 113–120.
- Webmineral data
- Vesuvianite at Franklin-Sterling
- Mindat - Cyprine variants with location data
