Nenadkevichite is a rare
silicate
In chemistry, a silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is al ...
mineral containing
niobium
Niobium is a chemical element with chemical symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and ductile transition metal. Pure niobium has a Mohs hardness rating similar to pure titanium, and it has sim ...
with the chemical formula . It forms brown to yellow to rose colored
orthorhombic
In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...
dipyramidal crystals with a dull to earthy
luster. It has a
Mohs hardness of 5 and a
specific gravity of 2.86.
It was first reported in 1955 from a
nepheline syenite pegmatite
A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic com ...
in the
Kola Peninsula. In addition it has been reported from
Mont Saint-Hilaire,
Canada; the
Ilimaussaq complex,
Greenland;
Windhoek District
Windhoek (, , ) is the capital and largest city of Namibia. It is located in central Namibia in the Khomas Highland plateau area, at around above sea level, almost exactly at the country's geographical centre. The population of Windhoek in 202 ...
,
Namibia; and
Zheltye Vody,
Ukraine. It was named after
Konstantin Avtonomovich Nenadkevich
The first name Konstantin () is a derivation from the Latin name ''Constantinus'' (Constantine) in some European languages, such as Russian and German. As a Christian given name, it refers to the memory of the Roman emperor Constantine the Great. ...
(1880–1963),
Russian
mineralogist and
geochemist.
References
Webmineral data
Calcium minerals
Sodium minerals
Niobium minerals
Titanium minerals
Cyclosilicates
Orthorhombic minerals
Minerals in space group 55
{{Silicate-mineral-stub