BRUCITE
BRUCITE Brucite – Mg(OH)2 – is a relatively rare hydroxide. It is an important industrial mineral, being a source of the metal magnesium and of magnesia, in addition to applications in refractories, plastics and many other uses. It is classified in the Brucita Group. Very rarely it forms large crystals, but the literature reports cases […]
BARYTE
BARYTE Baryte – BaSO4 – is a relatively common sulfate, being the main ore mineral of Ba. Baryte crystals can exhibit a characteristic chisel-like shape, so one of the German names is “Meisselspat” (“Meissel” = chisel, “spat” = cleaved crystal). The crystals reach lengths of up to 85 cm. More than 70 different combined forms […]
BOULANGERITE
BOULANGERITE Boulangerite – Pb5Sb4S11 – is a relatively common sulphosalt that integrates Pb-Sb-Cu polymetallic ores. It constitutes Pb ore, as it contains 54.88% Pb (and 26.44% Sb). It has a very typical acicular habit, which is why it is called “feather-ore”. The crystals do not closely resemble fibers or feathers, but resemble an aggregate of […]
BORNITE
BORNITE Bornite – Cu5FeS4 – is a frequent sulfide, being one of the most important copper ore minerals. Bornite crystallizes in the Cubic System at temperatures ~ 200ºC. With lowering the temperature, the structure recrystallizes to orthorhombic, but any crystals already formed remain with the original cubic forms. May contain traces of Ag, Ge, Bi, […]
BISMUTH
BISMUTH Bismuth – Bi – is a relatively rare native element, occurring mainly in the Bi-Co-Ni-Ag-Sn paragenesis. The main ores of Bi are bismuthinite and bismite; native bismuth is not an important ore in this context. Most of the Bi is obtained as a byproduct from Pb, W and Cu ores. Bismuth is currently replacing […]
BRONZITE
BRONZITE See “Enstatite”
BITOWNITE
BITOWNITE See “PLAGIOCLASE”
BERTRANDITE
BERTRANDITE Bertrandite – Be4Si2O7(OH)2 – is a rarer (or less recognized!) sorosilicate, an alteration of beryl in Be-rich granitic pegmatites. It is the second most important Be ore, after beryl. It forms crystals with a maximum length of 5 cm. It may contain Fe, Ca, and Al. There is a colloidal vitreous variety. It is […]
BADDELEYITE
BADDELEYITE Baddeleyite – ZrO2 – is a rare oxide. It constitutes a Zr ore and has great applications in geochronology. Caldasite (or zirkite) is a rock composed of zircon and baddeleyite, a mixture of 25% zirconium oxide and 75% zirconium silicate, initially identified in Poços de Caldas (MG). It is an important zirconium ore, radioactive, […]
BERYL
BERYL Beryl – Be3Al2(Si6O18) – is a cyclosilicate that typically occurs in granitic pegmatites, being an important beryllium ore. Macroscopically, beryl, when massive and light in color, can easily be confused with several other minerals typical of pegmatites, including quartz and feldspars. Occurring in pegmatites, beryl can form crystals of gigantic dimensions. The largest crystal, […]