Vesuvianite

vesuvianite

monticellite

akermanite

melilite

Images

Formula: (Ca,Na)₁₉(Al,Mg,Fe)₁₃(SiO₄)₁₀(Si₂O₇)₄(OH,F,O)₁₀
Sorosilicate (Si₂O₇ groups), vesuvianite group
Crystal System: Tetragonal
Specific gravity: 3.32 to 3.43 measured, 3.42 calculated
Hardness: 6½
Streak: White
Colour: Brown, yellow, brown-black, light green, emerald green, white, red, purple, violet, blue-green to blue
Solubility: Slightly soluble in hydrochloric acid
Common impurities: Fe,Be,B,F,Cu,Li,Na,K,Mn,Ti,Cr,Zn,H₂O
Environments:

Plutonic igneous environments
Volcanic igneous environments
Pegmatites (USGS bulletin 445 Pegmatites of Maine)
Carbonatites
Metamorphic environments (typical)

Vesuvianite is usually formed as the result of contact and regional metamorphism of impure limestone. In contact metamorphism it is associated with other contact metamorphic minerals, such as grossular, andradite, wollastonite and diopside. It is also found in garnet-bearing gabbro, in nepheline syenite and in veins associated with mafic rocks and serpentinite.
Vesuvianite may be found in nepheline syenite, gabbro, limestone, skarn and serpentinite.

In metamorphic rocks vesuvianite is stable from temperatures below 300^oC to above 900^oC, depending on pressure.
In low-grade metamorphic environments with temperature below 300^oC, major associated minerals are xonotlite, wollastonite, natrolite, thomsonite, pectolite and calcite, and other minerals that might be present include kirschsteinite, glaucochroite, aegirine, åkermanite, tobermorite, hydromagnesite and vuagnatite.
In medium grade metamorphic environments with temperature from about 300^oC to 500^oC, major associated minerals are grossular, diopside, magnesium-rich chlorite, prehnite, epidote and calcite, and other minerals that might be present include albite, titanite, apatite, dolomite, perovskite and zircon.
In high grade metamorphic environments, with temperatures above 500^oC, major associated minerals are grossular, diopside, wollastonite, calcite, monticellite, melilite and quartz, and other minerals that might be present include spinel, epidote, plagioclase and zoisite (Lauf p146).

Occasional pseudomorphs of vesuvianite after melilite and after mica, presumably phlogopite, have been found (Lauf p168).

Localities

At the Pinchon marble quarry, near Malone, Ontario, Canada, vivianite crystals to 10 cm occur in the Grenville Province skarn (Lauf p148).

In the St Jovite area, Laurentides, Quebec, Canada, vesuvianite occurs in a regional metamorphic environment in calcite marble in a lens consisting of calcite, microcline, vesuvianite, quartz, diopside, calcium-rich plagioclase and wollastonite (Lauf p150).

At Mont Saint-Hilaire, Montérégie, Quebec, Canada, vesuvianite is found in xenoliths within the nepheline syenite, but more commonly in the contact zone between marble and syenite (Lauf p146).

At the Jeffrey quarry, Asbestos, Quebec, Canada, vesuvianite is found in hydrothermal veins in serpentinite, formed at 300 to 400^oC and a pressure of 0 to 2 kbar (Lauf p150).

At the Fushan Mine, She County, Handan, Hebei, China, vesuvianite is found as large, sharp, lustrous, tetragonal crystals (AESS)
Vesuvianite from Fushan - Image

At Sha Lo Wan, Lantau Island, Islands District, New Territories, Hong Kong, China, the exposed skarn zone is about 5 m wide, and is composed mainly of garnet, vesuvianite, diopside and epidote, with scattered magnetite (Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council).

The Ma On Shan Mine, Ma On Shan, Sha Tin District, New Territories, Hong Kong, China, is an abandoned iron mine, with both underground and open cast workings. The iron ores contain magnetite as the ore mineral and occur predominantly as masses of all sizes enclosed in a large skarn body formed by contact metasomatism of dolomitic limestone at the margins of a granite intrusion. In parts of the underground workings magnetite is also found in marble in contact with the granite. The skarn rocks consist mainly of tremolite, actinolite, diopside and garnet. Vesuvianite is found occasionally as small grains in the skarn rocks, associated with garnet, actinolite, epidote, fluorite and magnetite (Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council)

In Hunan, China, a cluster of large, well formed brown, vitreous, translucent crystals of vesuvianite has been found (AESS).
Vesuvianite from Hunan - Image

At the Shijiang Shan-Shalonggou mining area, Inner Mongolia, China, the mineral deposits occur predominantly in veins of hydrothermal origin in skarn. Vesuvianite is associated with cuspidine, as well-formed prisms to about 15 mm in length, that are nearly black, indicating a high iron content (R&M 96.5.404).

In Xinjiang, China, probably from Karakul Lake, butterscotch coloured, almost opaque vesuvianite has been found (AESS).
Vesuvianite from Xinjiang - Image

At Lough Anure, County Donegal, Ireland, vesuvianite occurs in skarn associated with wollastonite, grossular, diopside and tremolite (Lauf p148).

At Bellecombe, Châtillon, Aosta Valley, Italy, vesuvianite occurs with grossular (R&M 94.5.442).
Vesuvianite from Bellecombe - Image

At the type locality, Mount Somma, Somma-Vesuvius Complex, Naples, Campania, Italy, vesuvianite is found in limestone blocks that have been ejected from the volcano and undergone intense thermal metamorphism, at 600 to 1050^oC and a pressure of 0 to 2 kbar (Lauf p146).
Vesuvianite from Mount Somma - Image

Near the Arusha to Nairobi highway, between Kajiado and Namanga, Kenya, vesuvianite is found in a skarn deposit in crystalline limestone (Lauf p162).

At the Bau mining district, Sarawak, Malaysia, an antimony-rich vesuvianite has been reported, in a skarn-like rock where the ore is rich in stibnite and contains abundant wollastonite, epidote, quartz and calcite (Lauf p148).

At Lake Jaco, Coahuila, Mexico, vesuvianite occurs in skarn in an assemblage including calcite, quartz, grossular, vesuvianite, wollastonite and scapolite (Lauf p161).
Vesuvianite from Caohuila - Image

In the Zhob valley, Baluchistan, Pakistan, vesuvianite has been found in serpentinite (Lauf p162).

In‌ the Swiss and Italian Alps vesuvianite is found in serpentinite of various metamorphic grades from 200 to 800^oC and pressure from 0 to 6.5 kbar (Lauf p150).

In Tuva, Russia, metamict vesuvianite occurs in alkaline pegmatite associated with nepheline, microcline, thomsonite, other zeolites, cancrinite and albite (Lauf p146,165).

In the Wilui River region, Yakutia, Russia, a chlorine-rich vesuvianite occurs in rodingite-like metamorphic rocks associated with clinochlore, diopside, calcite, serpentine and garnets of the grossular - andradite series (Lauf p168).

At Långban, Sweden, bismuth-rich vesuvianite occurs in skarn associated with barium-rich K-feldspar, albite-rich plagioclase, lead-rich scapolite and phlogopite, with minor lead-rich epidote, vesuvianite and calcium-rich garnet (Lauf p168).
Vesuvianite from Långban - Image

At the Kachuik pluton, Seward peninsula, Alaska, USA, a metamict uranium and thorium bearing vesuvianite has been found in a radioactive syenite deposit with allanite, K-feldspar, hornblende and clinopyroxene (Lauf p146,165).

At the Crestmore quarry, Riverside county, California, USA, vesuvianite occurs in skarn (Lauf p157).
Vesuvianite from Crestmore - Image

At outcrops near the Dallas benitoite mine, San Benito county, California, USA, cerium-rich vesuvianite has been found associated with andradite variety melanite, perovskite and clinochlore (Lauf p164).
Vesuvianite from San Benito County - Image

At the Bill Waley Allotment tungsten mine, Tulare county, California, USA, vesuvianite occurs in a deposit formed at the contact between granodiorite and marble by metasomatic replacement. Other minerals in the assemblage include löllingite, calcite, epidote, wollastonite, pyrrhotite and chalcopyrite (Lauf p157).
Vesuvianite from the Bill Waley Allotment Tungsten Mine - Image

At Sanford, Maine, USA, crystals of vesuvianite to 17 cm are associated with quartz and occasionally with calcite, in a calc-silicate rock (Lauf p157).
Vesuvianite from Sanford - Image

At Manchester, New Hampshire, USA, vesuvianite is associated with garnet and scapolite in altered calcareous bands interbedded with lenses of granite and pegmatites (Lauf p148).

At Franklin, New Jersey, USA, beryllium-rich vesuvianite has been found as crystals embedded in a mixture of willemite, garnet, leucophoenicite, baryte and other species (Lauf p167).
Vesuvianite from Franklin - Image

Alteration

grossular, diopside, monticellite, calcite and H₂O to vesuvianite, quartz and CO₂
10Ca₃Al₂(SiO₄)₃ + 3CaMgSi₂O₆ + 3CaMg(SiO₄) + 2CaCO₃ + 8H₂O ⇌ 2Ca₁₉Al₁₀Mg₃(SiO₄)₁₀ (Si₂O₂)₄O₂(OH)₈ + 3SiO₂ + 2CO₂
A common association in calc-silicate metamorphism can be represented by the above equation. Vesuvianite stability will tend to increase with increasing water and decrease as the activity of CO₂ rises (DHZ 1A p714).

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