Nosean, otherwise called Noselite, is a mineral of the feldspathoid type in tectosilicate with formula: Na8Al6Si6O24 (SO4). H2O. It frames isometric precious stones of variable shading: white, dim, blue, green, to dark colored. It has a Mohs hardness of 5.5 to 6 and a particular gravity of 2.3 to 2.4. It is fluorescent. It is found in low silica volcanic rocks. There is a strong arrangement among nosean and hauyne, which contains calcium.
Name: After Karl Wilhelm Nose (1753?{1835), German mineralogist, of Brunswick (now Lower Saxony), Germany
Association: Sanidine, mica, leucite, magnetite, ilmenite, titanite, zircon.
Occurrence: In silica-decient alkalic volcanic rocks, principally phonolites.
Mineral Group: Sodalite group.
Cell Data: Space Group: P43n: a = 9.05{9.08 Z = 1
Contents
Chemical Properties
| Chemical Classification | Tectosilicate (Feldspathoid) |
| Formula | Na8(Al6Si6O24)(SO4) · H2O |
| Common Impurities | Al, H, Na, O, S, Si |
Nosean Physical Properties
| Color | Colorless, white, gray, gray-brown, blue, black |
| Streak | Bluish white |
| Luster | Vitreous |
| Cleavage | Poor/Indistinct Indistinct on {110} |
| Diaphaneity | Transparent, Translucent |
| Mohs Hardness | 5,5 |
| Crystal System | Isometric |
| Tenacity | Brittle |
| Density | 2.3 – 2.4 g/cm3 (Measured) 2.21 g/cm3 (Calculated) |
| Fracture | Irregular/Uneven, Conchoidal |
| Morphology | dodecahedra, grains, massive |
Nosean Optical Properties
| Type | Isotropic |
| Color / Pleochroism | Non-pleochroic |
| RI values: | n = 1.461 – 1.495 |
| Twinning | on {111} |
| Birefringence | Isotropic minerals have no birefringence |
| Relief | Moderate |
Distribution
- In Germany, at the Schellkopf, near Brenk, and elsewhere around the Laacher See, Eifel district; at Dutchlingen and in the HÄowenegg quarry, Hegau, Baden-WuÄrttemberg.
- In the Mont-Dore massif, Auvergne, and at Vinsac, Aldis, and Cournil, Cantal, France.
- At Wolf Rock, Cornwall, England.
- From Covao, Cape Verde Islands.
- South of the Col de Maza, Morocco.
- From the Black Hills, Lawrence Co., South Dakota, and in the Cripple Creek district, Teller Co., Colorado, USA.
- From the Lovozero massif, Kola Peninsula, Russia.
- On Hsi Kuang T’a Men Mountain, Chiao Ch’eng Mountains, Shansi Province, China.
References
- Handbookofmineralogy.org. (2019). Handbook of Mineralogy. [online] Available at: http://www.handbookofmineralogy.org [Accessed 4 Mar. 2019].
- Mindat.org. (2019): Mineral information, data and localities.. [online] Available at: https://www.mindat.org/ [Accessed. 2019].
