Lueshite Locality: Lueshe Mine, Kivu , Democratic Republic of Congo (Zaïre) ( Locality at mindat.org ) Size: thumbnail, .6 x .6 x .6 cm Lueshite Exceptional cube of the rare niobium-containing species Lueshite, with good metallic luster and typical back-silver color. What makes this so grand is the size and, most especially, the sharpness of the crystal. I am told that these came out only sporadically, and mostly 20-plus years ago. This is the largest I have had for sale out of several over the years. It is a significant example for the species. .6 x .6 x .6 cm — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Lueshite
Lueshite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula NaNbO₃.
It crystallizes in the trigonal crystal system (space group Pbma). It is a member of the Perovskite structural group.
Key properties: Mohs hardness 5–5.5; specific gravity 4.44; Gray streak; Submetallic luster; optically biaxial.
IMA symbol Lue, IMA status: approved, named in 1959.
Incrusting a vermiculitelike mica, at the contact of cancrinite syenite with carbonatite (Lueshe, Congo); in sodalite xenoliths in association with an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada).
It is found associated with Mica (Lueshe, Congo); sodalite, ussingite, villiaumite, steenstrupine, griceite, eudialyte, lovozerite (Mont Saint-Hilaire, Canada); vermiculite, ilmenite.
The name refers to the occurrence at Lueshe, Congo.