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Fornacite is a rare lead, copper chromate arsenate hydroxide mineral with the formula: Pb2Cu(CrO4)(AsO4)(OH). It is a monoclinic-prismatic mineral containing arsenic, chromium, copper, hydrogen, lead,…

Triangle is a plane figure with three straight sides and three angles. The three angles always add to 180°. The vertex is a corner of the…

Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It is a halide mineral composed of calcium fluoride. It crystallizes in isometric…

Fluorellestadite is a rare nesosilicate of calcium, with sulfate and fluorine, with the chemical formula Ca10(SiO4)3(SO4)3F2. It is a rare nesosilicate of calcium, with sulfate…

Fluororichterite is a rare amphibole with formula Na(NaCa)Mg5Si8O22F2. It was recognized by the International Mineralogical Association in 1994. Its name is derived from its fluorine…

Triangle is a plane figure with three straight sides and three angles. The three angles always add to 180°. The vertex is a corner of the…

Fluorcaphite is a mineral with the chemical formula (Ca, Sr, Ce, Na)5(PO4)3F. It is a hexagonal-pyramidal mineral containing calcium, cerium, fluorine, oxygen, phosphorus, sodium, and…

Fluorapophyllite is a mineral of the apophyllite group, with the chemical formula of KCa4Si8O20(F, OH)·8(H2O). It is a particular apophyllite mineral with more fluorine than…

Medians of a Triangle A median of a triangle is a line segment joining a vertex to the midpoint of the opposite side. Triangle is…

Fluorapatite, often with the alternate spelling of fluoroapatite, is a phosphate mineral with the formula Ca5(PO4)3F (calcium fluorophosphate). It is a crystalline mineral, formed from…

Fluor-uvite is a tourmaline mineral with the chemical formula CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3F. It is a rare mineral that is found in calcium-rich contact metamorphic rocks with increased…

Fluor-liddicoatite is a rare member of the tourmaline group of minerals and elbaite subgroup. It forms a series with elbaite and probably also with olenite.…