PHLOGOPITE
PHLOGOPITE Phlogopite – K2Mg6Al2Si6O20(OH,F)4 – is a rarer phyllosilicate, but relatively common in parageneses with carbonates. It is an important industrial mineral. It is the second most mined mica, after muscovite. Phlogopite is part of the biotite series, which consists of: phlogopite (Fe 0-20%, Mg 100-80%), meroxene (Fe 20-50%, Mg 80-50%), lepidomelane (Fe 50-80%, Mg […]
PIEMONTITE
PIEMONTITE Piemontite – Ca2(Al,Mn3+,Fe3+)3O(Si2O7)(SiO4)(OH) – is a sorosilicate with a very restricted distribution. It has no economic importance. Piemontite is one of the members of the Epidote Group. It can contain Na, K, Fe, Ti and H2O and there is a variety with Sr. In many cases, a deep red variety of epidote, containing Mn3+, […]
PARAREALGAR
PARAREALGAR See “ORPIMENT”
PYROLUSITE
PYROLUSITE Pyrolusite – Mn4+O2 – is an oxide that constitutes one of the most important Mn ore minerals. In manganese mining, a term used is “wad”, attributed to a mixture of manganese minerals formed by submicroscopic grains mainly of pyrolusite and psilomelane. Pyrolusite is classified in the Rutile Group and is trimorphic with akhtenskite and […]
PSEUDOLEUCITE
PSEUDOLEUCITE Pseudoleucite is a pseudomorph of nepheline + orthoclase over the original leucite. The typical cubic form of leucite, the trapezohedron, may be preserved, but generally only rounded forms are observed. Leucite is typical of K-rich and silica-deficient volcanic rocks, almost exclusively occurring as phenocryst in undersaturated (mafic and alkaline) volcanic and hypabyssal rocks, such […]
POLLUCITE
POLLUCITE Pollucite – (CsNa)2(Al2Si4O12).2H2O – is a very rare tectosilicate that occurs in lithiniferous granitic pegmatites and constitutes the most important ore of Cs. Cesium is important to the oil industry. It is classified in the Zeolite Group and is part of the Analcime-Pollucita series, constituting the Cs analogue of analcime (of Na), with which […]
PSILOMELANE
PSILOMELANE Psilomelane – general formula: (Ba,H2O)2Mn5O10 – does not designate a mineral species. It is an old term, nowadays less used, referring to a set of black, hard and hydrated oxides of manganese that can contain Ba, Cu, Co, Ni, Mg, Ag, Ca, W and K. It is a mining term, very practical, used when […]
PYRRHOTITE
PYRRHOTITE Pyrrhotite – Fe(1-x)S (x= 0 – 0.2) – is a relatively common sulfide, frequent as an accessory in many types of igneous rocks and ores. It is not a major ore mineral, but it is mined because it occurs in association with pentlandite, an ore of nickel and cobalt. Generates a mine effluent of […]
PLAGIOCLASE
PLAGIOCLASE Plagioclase – NaAlSi3O8 – CaAl2Si2O8 – is a very common rock-forming tectosilicate, the second most abundant mineral in the Earth’s crust, just behind quartz. It is an industrial mineral with many uses. “Plagioclase” is not actually a mineral, but a term used for the members of the solid solution between albite (Ab) (NaAlSi3O8) and […]
PHOSPHORITE
PHOSPHORITE Phosphorus is a strategic element, as it is essential for agriculture, integrated into NPK fertilizers. There is no substitute for P in agriculture. Phosphate is also widely used as an animal feed supplement and in the chemical industry. The only sources of P are the so-called “phosphate rocks,” which can be of two types: […]