Nabalamprophyllite
Encyclopedia
Nabalamprophyllite has a general formula of Ba(Na,Ba){Na3Ti[Ti2O2Si4O14](OH,F)2} The name is given for its composition (Naba, meaning sodium, Na and barium, Ba) and relation to other lamprophyllite-group minerals. Lamprophyllite is a rare Ti-bearing silicate mineral usually found in intrusive igneous rocks.
Nabalamprophyllite is monoclinic, which means crystallographically, it contains three axes of unequal length and the angles between two of the axes are 90°, and one is less than 90°. It belongs to the space group
P2/m. The mineral also has an orthorhombic polytype (nabalamprophyllite-2O) This mineral belongs to the space group Pnmn. In terms of its optical properties, nabalamprophyllite is anisotropic which means the velocity of light varies depending on direction through the mineral. Its calculated relief
is 1.86 - 1.87. Its color in plane polarized light is green-brown, and it is weakly pleochroic.
The mineral has only been found in Russia
, usually in association with coarse-grained igneous rocks called pegmatites. The type localities are the Inagli alkaline–ultrabasic massif, Yakutia and the Kovdor
alkaline–ultrabasic massif in the Kola Peninsula
.
Nabalamprophyllite is monoclinic, which means crystallographically, it contains three axes of unequal length and the angles between two of the axes are 90°, and one is less than 90°. It belongs to the space group
Space group
In mathematics and geometry, a space group is a symmetry group, usually for three dimensions, that divides space into discrete repeatable domains.In three dimensions, there are 219 unique types, or counted as 230 if chiral copies are considered distinct...
P2/m. The mineral also has an orthorhombic polytype (nabalamprophyllite-2O) This mineral belongs to the space group Pnmn. In terms of its optical properties, nabalamprophyllite is anisotropic which means the velocity of light varies depending on direction through the mineral. Its calculated relief
Relief
Relief is a sculptural technique. The term relief is from the Latin verb levo, to raise. To create a sculpture in relief is thus to give the impression that the sculpted material has been raised above the background plane...
is 1.86 - 1.87. Its color in plane polarized light is green-brown, and it is weakly pleochroic.
The mineral has only been found in Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, usually in association with coarse-grained igneous rocks called pegmatites. The type localities are the Inagli alkaline–ultrabasic massif, Yakutia and the Kovdor
Kovdor
Kovdor is a town and the administrative center of Kovdorsky District of Murmansk Oblast, Russia, mostly known by its mining industry. Population: -Economy:...
alkaline–ultrabasic massif in the Kola Peninsula
Kola Peninsula
The Kola Peninsula is a peninsula in the far northwest of Russia. Constituting the bulk of the territory of Murmansk Oblast, it lies almost completely to the north of the Arctic Circle and is washed by the Barents Sea in the north and the White Sea in the east and southeast...
.