Where it forms, where it's found
- Geological setting
dolomite carbonatites
- Type locality
- Lesnaya Varaka Massif
- Murmansk Oblast
- Russia
67.3833°, 33.0667°
6recorded occurrences
Physical
- Hardness
- 1Talc
- 2Gypsum
- 3Calcite
- 4Fluorite
- 5Apatite
- 6Orthoclase
- 7Quartz
- 8Topaz
- 9Corundum
- 10Diamond
- Transparency
- Opaque
- Colour
- Variable. Light gray-black · also light brown to pale yellow.
- Tenacity
- brittle
- Density
- 4.40 g/cm³
Optical
- Optical type
- Biaxial (+) · 2V measured = 10 – 30° · 2V calc = 48 – 60°
- Refractive index
- 2.1 – 2.24
- Surface relief
- Very high
- Principal indices
- nα 2.10 – 2.13 · nβ 2.19 – 2.21 · nγ 2.21 – 2.24
- Birefringence
- 0.11
- Dispersion
- r < v
- UV response
- Not fluorescent in UV
Δ = 0Δmax
PPLpleochroism per grain
XPLindependent extinctions · rotate the stage
PPLpleochroism only · colour blends on rotation
XPLinterference colour · extinct every 90°
Retardation1100 nm
Order2nd order
XPL colour
Crystallography
- Type-locality form
irregular grains and in fine-grained aggregates
- Comment
Monoclinic, probable. Point Group: n.d.; Space Group: n.d. Z = n.d.
Chemical composition
Synonyms
- Natroniobiet
In other languages
- German
- Natroniobit
- Italian
- Natroniobite
Classification
Strunz
10th ed.4.CC.30
- 4OxidesClass
- 4.CMetal: Oxygen = 2: 3,3: 5, and similarDivision
- 4.CCWith large and medium-sized cationsGroup
- 4.CC.30NatroniobiteSpecies
Dana
8th ed.04.03.04.01
- 04Simple OxidesClass
- 04.03A2X3Type
- 04.03.04— unnamed intermediate level —Group
- 04.03.04.01NatroniobiteSpecies
CIM
—18.1.3
- 18Niobates and TantalatesClass
- 18.1Niobates and tantalates containing neither rare earths nor UGroup
- 18.1.3NatroniobiteSpecies
Group, growth & confusion
Literature, links & citation
Citations
- —Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva: 92: 190.
- 1960Bulakh A G, Kukharenko A A, Knipovich Y N, Kondrat'eva V V, Baklanov K A, Baranova E N (1960) Some new minerals in carbonatites of the Kola Peninsula. Ministry of Geology and Mineral Protection of the USSR All-Union Research Geological Institute (Total), Proceedings of the annual session of the Academic Council on the results of work in 1959 1960, 114-116
- 1961Solov'ev, S.P., Venevtsev, Y.N., Zhdanov, G.S. (1961) An X-ray study of phase transitions in NaNbO3. Soviet Physics - Crystallography: 6: 171-175.
- 1962Fleischer, Michael; František, Čech (1962) New mineral names. American Mineralogist, 47 (11-12). 1482-1485
- 2005(2005) Natroniobite. Handbook of Mineralogy. Mineralogical Society of America
Cite this entry
@misc{mineral2026,
author = {Mineral Index editorial board},
title = {Natroniobite — Mineral Index},
year = {2026},
url = {https://mineralindex.org/minerals/natroniobite-2860},
note = {Accessed 2026-05-11}
}