Canavesite
Encyclopedia
Canavesite, Mg2(CO3)∙5H2O, is a rare carboborate mineral from the abandoned Brosso mine in Italy. Canavesite is a secondary mineral that occurs due to the weathering of ludwigite-magnetite skarn on the surface of mine walls. The physical properties consist of a milky-white rosette-like aggregates of elongated transparent fibers shown in figure one . It has the crystal symmetry of a monoclinic with a diffraction symbol of 2/mP-/-.
where in 1964 Giussani & Vighi saw and described boron
mineralization. They noticed secondary minerals forming between szaibelyite and ludwigite
at the point where they come into contact with each other inside magnetite
skarns. Years later in 1972 a few members from the Gruppo Mineralogico Lombardo found the first sample of a new unknown mineral around the same location. Since then canavesite has been traded as nesquehonite and added to geologic collections. Canavestie is one of few carboborates known to man. The name canavesite originates from the district of Canavese where the pyrite
mine is located .
ions, one can calculate from this data the empirical formula is as followed Mg2.03(HBO3)1.09(CO3)∙4.91H2O . A canavestie infrared spectrum is unlike that of well know families. It has bands near 3500, 1450, and 1000 cm-1 looks almost like OH-. With a dilute HCl
at or near room temperature canavestie will produce tiny bubbles of gas and foam with hissing sounds. The molecular formula has not been obtained for canavesite. The approximate density was obtained using the heavy liquid method, which shows a density of 1.8 g cm−3.
in Canavese district. The mine was initially a pyrite mine but it was abandoned. It is a well known mine for fine minerals that build up between the zone where monzonite
stock and marbles interbedded in the mica schists of the Sesia-Lanzo zone. Mineralization of boron
within magnetite
skarns were first reported by Giussani and Vighi in 1964 . There has since been more canavesite discovered in New Jersey
at the Sterling Mine. They are the only two places that have been known to produce the secondary mineral.
and magnetite
skarns . Canavesite is an exceptionally rare secondary mineral that forms on the walls of the abandoned mine of Brosso, Italy
and has formed since the mine was abandoned due to weathering of these ludwigite
and magnetite
skarns. Canvesite has a monoclinic P 2/m crystal structure and does not fluoresce under an ultraviolent light. It also has thin and slightly flexible vitreous fibers that are elongated parallel to [010]. Some crystal may show pseudohexagonal prismatic habit, but these cases are rare. The X-ray powder diffraction pattern strongest lines are 9.54(100)202, 8.12(40)(201), 7.80(18)(102,301), 4.56(21)(501,503), and 3.11(19)(407).
History
The pyrite mine, Brosso, in ItalyItaly
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
where in 1964 Giussani & Vighi saw and described boron
Boron
Boron is the chemical element with atomic number 5 and the chemical symbol B. Boron is a metalloid. Because boron is not produced by stellar nucleosynthesis, it is a low-abundance element in both the solar system and the Earth's crust. However, boron is concentrated on Earth by the...
mineralization. They noticed secondary minerals forming between szaibelyite and ludwigite
Ludwigite
Ludwigite is a magnesium-iron borate mineral: Mg2FeBO5.Ludwigite typically occurs in magnesian iron skarn and other high temperature contact metamorphic deposits. It occurs in association with magnetite, forsterite, clinohumite and the borates vonsenite and szaibelyite...
at the point where they come into contact with each other inside magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...
skarns. Years later in 1972 a few members from the Gruppo Mineralogico Lombardo found the first sample of a new unknown mineral around the same location. Since then canavesite has been traded as nesquehonite and added to geologic collections. Canavestie is one of few carboborates known to man. The name canavesite originates from the district of Canavese where the pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...
mine is located .
Composition
Canavesite has the chemical formula,Mg2(HBO3)(CO3)∙5H2O ,which makes it a carboborate mineral . Having two complete chemical analyses and one partial gives MgO (31.06),B2O3(12.70),CO2(18.57)H2O(37.44) and MgO (31.18),B2O3(13.47),CO2(17.02)H2O(38.33) in weight % oxides. Taking eleven oxygenOxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
ions, one can calculate from this data the empirical formula is as followed Mg2.03(HBO3)1.09(CO3)∙4.91H2O . A canavestie infrared spectrum is unlike that of well know families. It has bands near 3500, 1450, and 1000 cm-1 looks almost like OH-. With a dilute HCl
HCL
HCL or HCl can stand for:* Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia* Hardware compatibility list...
at or near room temperature canavestie will produce tiny bubbles of gas and foam with hissing sounds. The molecular formula has not been obtained for canavesite. The approximate density was obtained using the heavy liquid method, which shows a density of 1.8 g cm−3.
Occurrence
The Vola Gera tunnel in the Brosso mine is located in a village northwest of Ivrea, Piedmont, ItalyItaly
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
in Canavese district. The mine was initially a pyrite mine but it was abandoned. It is a well known mine for fine minerals that build up between the zone where monzonite
Monzonite
Monzonite is an intermediate igneous intrusive rock composed of approximately equal amounts of sodic to intermediate plagioclase and orthoclase feldspars with minor amounts of hornblende, biotite and other minerals...
stock and marbles interbedded in the mica schists of the Sesia-Lanzo zone. Mineralization of boron
Boron
Boron is the chemical element with atomic number 5 and the chemical symbol B. Boron is a metalloid. Because boron is not produced by stellar nucleosynthesis, it is a low-abundance element in both the solar system and the Earth's crust. However, boron is concentrated on Earth by the...
within magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...
skarns were first reported by Giussani and Vighi in 1964 . There has since been more canavesite discovered in New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
at the Sterling Mine. They are the only two places that have been known to produce the secondary mineral.
Physical properties
Canavesite occurs as a milky rosette-like aggregates of very thin [010] elongated fibers on surfaces and along fractures of ludwigiteLudwigite
Ludwigite is a magnesium-iron borate mineral: Mg2FeBO5.Ludwigite typically occurs in magnesian iron skarn and other high temperature contact metamorphic deposits. It occurs in association with magnetite, forsterite, clinohumite and the borates vonsenite and szaibelyite...
and magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...
skarns . Canavesite is an exceptionally rare secondary mineral that forms on the walls of the abandoned mine of Brosso, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
and has formed since the mine was abandoned due to weathering of these ludwigite
Ludwigite
Ludwigite is a magnesium-iron borate mineral: Mg2FeBO5.Ludwigite typically occurs in magnesian iron skarn and other high temperature contact metamorphic deposits. It occurs in association with magnetite, forsterite, clinohumite and the borates vonsenite and szaibelyite...
and magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...
skarns. Canvesite has a monoclinic P 2/m crystal structure and does not fluoresce under an ultraviolent light. It also has thin and slightly flexible vitreous fibers that are elongated parallel to [010]. Some crystal may show pseudohexagonal prismatic habit, but these cases are rare. The X-ray powder diffraction pattern strongest lines are 9.54(100)202, 8.12(40)(201), 7.80(18)(102,301), 4.56(21)(501,503), and 3.11(19)(407).