Tanteuxenite-(Y)

General Information: Chemical Formula:(Y,Ce,Ca)(Ta,Nb,Ti)2(O,OH)6 Composition:(Molecular Weight = 480.83 gm)Calcium 1.67 % CaCerium 2.91 % CeYttrium 12.94 % Y Tantalum 52.69 % TaTitanium 1.99 % TiNiobium 7.73 % NbHydrogen 0.10 % H Oxygen 19.96 % O  Empirical Formula: Y0.7Ca0.2Ce0.12(Ta0.7)2(Nb0.2)2(Ti0.1)O5.5(OH)0.5 Environment:Tin placers. IMA Status:Approved IMA 1987 Locality:Cooglegong, Pilbara, WA, Australia. Name Origin:Named for the composition (Tantalum) and the Greek for "friendly to strangers, hospitable," in allusion to the rare elements that it contains.Physical Properties: Cleavage:[???] Indistinct Color:brownish black. Density:5.4 - 5.9, Average = 5.65 Diaphaniety:Subtranslucent to Opaque Habits:Indistinct - Crystals or grains are unremarkable or poorly formed. Anhedral to subhedral crystals., Tabular - Form dimensions are thin in one direction., Metamict - Mineral originally crystalline, now amorphous due to radia Hardness:5-6 - Between Apatite and Orthoclase Luster:Resinous Streak:brownish grayMore details...