Nosean

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

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].