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Theorem of Three Perpendiculars A line is said to be perpendicular to another line if the two lines intersect at a right angle. Explicitly, a…

Euxenite or euxenite-(Y) is a brownish black mineral with a metallic luster. It is a mineral that is sometimes called a “trash can mineral”. Because…

Zirsilite-(Ce) is a very rare mineral of the eudialyte group, with formula (Na,[])12(Ce, Na)3 Ca6 Mn3Zr3NbSi(Si9O27)2(Si3O9)2O(OH)3(CO3)•H2O. The original formula was extended to show the presence…

Voronkovite is a very rare mineral of the eudialyte group with the formula Na15(Na, Ca, Ce)3(Mn, Ca)3Fe3Zr3Si2Si24O72(OH, O)4Cl·H2O. It is a trigonal-pyramidal yellowish-brown mineral containing…

Converse of the theorem on parallel lines and plane: Theorem: If two straight lines are parallel and if one of them is perpendicular to a…

Taseqite is a rare mineral of the eudialyte group, with formula Na12Sr3Ca6Fe3Zr3NbSiO(Si9 O27)2(Si3O9)2(O, OH, H2O)3Cl2. It occurs in a cavity in a late-stage hydrothermal albitite…

Rastsveatevite is a rare mineral of the eudialyte group with the formula Na27K8Ca12Fe3Zr6Si4[Si3O9]4[Si9O27]4(O, OH, H2O)6Cl2. It is a trigonal-ditrigonal pyramidal pink mineral containing calcium, chlorine,…

Theorem on Parallel Lines and Plane Theorem: If two straight lines are parallel and if one of them is perpendicular to a plane, then the…

Raslakite is a rare mineral of the eudialyte group with the formula Na15 Ca3Fe3(Na,Zr)3Zr3(Si,Nb)SiO(Si9O27)2(Si3O9)2(OH,H2O)3(Cl,OH). It is a trigonal-ditrigonal pyramidal brownish-red mineral containing calcium, chlorine, hydrogen,…

Oneillite is a rare mineral of the eudialyte group with the formula Na15Ca3Mn3Fe23+Zr3NbSiO(Si3O9)2(Si9O27)2(O,OH,H2O)3(OH,Cl)2. It was named for John Johnston O’Neill, as a geologist with the…

Mogovidite is a very rare mineral of the eudialyte group, with formula Na9(Ca,Na)6Ca6(Fe3+,Fe2+)2 Zr3[]Si(Si9O27)2(Si3O9)2(CO3)(OH, H2O)4. It occurs in a nepheline-pectolite vein within ijolite. The formula given…

Theorem on Co-planar A set of points, lines, line segments, rays or any other geometrical shapes that lie on the same plane are said to…