Polished section of the three very rare tantalum minerals: cesplumtantite, lithiotantite and calciotantite, in an specimen that was analyzed by the former owner of the specimen (the Vandenbroucke Museum), associated to cassiterite, after the label. From: Manono-Kitotolo Mine, Tanganyika, DR Congo. Type locality for the first of them, cesplumtantite, that it is also a cesium mineral. Cesium minerals are extremely rare in Nature. Ex Vandenbroucke Museum collection from Waregem, Belgium — Photo: David Hospital · CC BY-SA 4.0
Cesplumtantite
Cesplumtantite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Cs₂Pb₃Ta₈O₂₄.
It crystallizes in the tetragonal crystal system.
Key properties: specific gravity 6.87; White streak; Adamantine luster.
IMA symbol Cptan, IMA status: approved, named in 1985.
Found in veinlets in a museum specimen from a granite pegmatite.
It is found associated with Lithiotantite, cassiterite, calciotantite, microlite, thoreaulite.
The name refers to CESium, lead (PLUMbum), and TANTalum in the composition.