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Cavansite, named for its chemical composition of ''calcium vanadium silicate'', is a deep blue hydrous calcium vanadium phyllosilicate mineral, occurring as a secondary mineral in basaltic and andesitic rocks along with a variety of zeolite minerals. Its blue coloring comes from vanadium, a metal ion. Discovered in 1967 in Malheur County,
Cavansite is a distinctive mineral. It tends to form crystal aggregates, generally in the form of balls, up to a couple centimeters in size. Sometimes, the balls are coarse enough to allow the individual crystals to be seen. Rarely, cavansite forms bowtie-shaped aggregates. The color of cavansite is distinctive, almost always a rich, bright blue. The color is the same as its dimorph, pentagonite, but the latter is generally much more spikey with bladed crystals. Finally, the associated minerals are useful for identification, as cavansite is frequently found sitting atop a matrix of zeolites or apophyllites.
Mineral galleries
* Evans, H.T. Jr., "The crystal structure of cavansite and pentagonite", American Mineralogist, Vol. 58, pg. 412–424, 1973. * Makki, M.F., "Collecting cavansite in the Wagholi quarry complex, Pune, Maharashtra, India", The Mineralogical Record, Vol. 36, No. 6, pg. 507–512, Nov-Dec 2005. * Staples, L.W., Evans, H.T. Jr., and Lindsay, J.R., "Cavansite and pentagonite, new dimorphous calcium vanadium silicate minerals from Oregon", American Mineralogist, Vol. 58, pg 405–411, 1973. http://www.minsocam.org/ammin/AM58/AM58_405.pdf
Oregon
Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...
, cavansite is a relatively rare mineral. It is polymorphic with the even rarer mineral, pentagonite. It is most frequently found in Pune
Pune ( ; , ISO 15919, ISO: ), previously spelled in English as Poona (List of renamed Indian cities and states#Maharashtra, the official name until 1978), is a city in the state of Maharashtra in the Deccan Plateau, Deccan plateau in Western ...
, India, and in the Deccan Traps, a large igneous province.
Uses of cavansite
Although cavansite contains vanadium, and could thus be a possible ore source for the element, it is not generally considered an ore mineral. However, because of its rich color and relative rarity, cavansite is a sought-after collector's mineral.Associated minerals
* Members of the apophyllite group * Members of the zeolite group, particularly stilbite * babingtonite, Ca2 Fe2 Si5 O14 OH *quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
, Si O2
* calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
, Ca CO3
* pentagonite, Ca( V O) Si4 O10 · 4( H2O)
Notes for identification
Cavansite is a distinctive mineral. It tends to form crystal aggregates, generally in the form of balls, up to a couple centimeters in size. Sometimes, the balls are coarse enough to allow the individual crystals to be seen. Rarely, cavansite forms bowtie-shaped aggregates. The color of cavansite is distinctive, almost always a rich, bright blue. The color is the same as its dimorph, pentagonite, but the latter is generally much more spikey with bladed crystals. Finally, the associated minerals are useful for identification, as cavansite is frequently found sitting atop a matrix of zeolites or apophyllites.
References
Mineral galleries
* Evans, H.T. Jr., "The crystal structure of cavansite and pentagonite", American Mineralogist, Vol. 58, pg. 412–424, 1973. * Makki, M.F., "Collecting cavansite in the Wagholi quarry complex, Pune, Maharashtra, India", The Mineralogical Record, Vol. 36, No. 6, pg. 507–512, Nov-Dec 2005. * Staples, L.W., Evans, H.T. Jr., and Lindsay, J.R., "Cavansite and pentagonite, new dimorphous calcium vanadium silicate minerals from Oregon", American Mineralogist, Vol. 58, pg 405–411, 1973. http://www.minsocam.org/ammin/AM58/AM58_405.pdf
External links
{{Commons-inline Calcium minerals Minerals in space group 62 Orthorhombic minerals Phyllosilicates Vanadium minerals Vanadyl compounds