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Fluckite is an arsenate mineral with the chemical formula CaMnH2(AsO4)2·2(H2O). It is a rare mineral of post-mine origin that forms as a low-temperature product of…

Fletcherite is a rare thiospinel sulfide mineral with formula Cu(Ni, Co)2S4. It is an isometric-hexoctahedral steel-gray mineral containing cobalt, copper, nickel, and sulfur. It is…

Fichtelite is a rare white mineral found in fossilized wood from Bavaria. It is a rare white monoclinic mineral found in fossilized wood from Bavaria.…

Fettelite, also known as sanguinite, is a mercury-sulfosalt mineral with the chemical formula Ag16HgAs4S15. It is a rare Silver Mercury Arsenic Sulfosalt forming silvery to…

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…

Orthorhombic ferroselite and its isometric polymorph dzharkenite are iron selenides of general formula FeSe2 precipitated under reducing conditions in anoxic environments. It is an orthorhombic-dipyramidal…

Ferropericlase or magnesiowüstite is a magnesium/iron oxide [(Mg, Fe)O] that is interpreted to be one of the main constituents of the Earth’s lower mantle together…

Order of a Surd Definitions of surds: A root of a positive real quantity is called a surd if its value cannot be exactly determined.…

Post-perovskite (pPv) is a high-pressure phase of magnesium silicate (MgSiO3). It is a high-pressure phase of several minerals, including magnesium silicate. It is composed of…

Ilmenite is the titanium-iron oxide mineral with the idealized formula FeTiO3. It is a common accessory mineral in igneous rocks, sediments, and sedimentary rocks in many…

Ferronigerite-2N1S is an iron, tin, alumino-hydroxide mineral that naturally occurs around sillimanite-quartz veins. It is very rarely found in gem-quality, cut-able material. Related to, and…

Induction Proof – Problems with Solutions Mathematical induction is a technique for proving a statement – a theorem, or a formula — that is asserted…