 |
|
|
Nosean is an uncommon member of the feldspathoid group that is closely related to Lazurite and Hauyne. It can sometimes be very difficult to distinguish these three minerals without a complex chemical analysis. Nosean forms a solid solution series with Hauyne, where Hauyne contains calcium in place of some of the sodium, whereas Nosean lacks any calcium and has water in its chemical structure.
|
|
|
Chemical Formula |
Na8Al6Si6O24(SO4) · H2O |
|
Composition |
Hydrous sodium calcium aluminum silicate with sulfate |
|
Color |
Bright blue, light blue, grayish-blue, gray, black, white, yellow, brown, colorless |
|
Streak |
Light blue to white |
|
Hardness |
5.5 |
|
Crystal System |
Isometric |
Crystal Forms
and Aggregates |
As coatings on interconnected dodecahedral crystals, in octahedral crystals, as complex prismatic microcrystals, grainy, and massive. |
|
Transparency |
Transparent to translucent |
|
Specific Gravity |
2.3 - 2.4 |
|
Luster |
Vitreous, waxy |
|
Cleavage |
1,2 |
|
Fracture |
Uneven |
|
Tenacity |
Brittle |
|
In Group |
Silicates; Tectosilicates; Feldspathoid Group |
|
Striking Features |
Color and mode of occurrence |
| Environment |
In alkali-rich, altered volcanic environments, nepehline syenites, and marbles. |
| Rock Type |
Igneous, Metamorphic |
|
Popularity (1-4)
|
3 |
|
Prevalence (1-3)
|
3 |
|
Demand (1-3) |
2 |
|
|
|
Exceptional Nosean with an electric-blue color comes from Sar-e Sang, Kokcha Valley, Badakshan Province, Afghanistan, where it forms most often as a significant inclusion of Sodalite coating Nepheline. Complex, prismatic colorless microcrystals of Nosean come from the In den Dellen quarries, Niedermendig, Eifel Mountains, Germany; and well-formed microcrystals from Vetralla, Vico Lake, Viterbo Province, Latium, Italy.
|
|
|
|
|
|
|
|
Have a question about Nosean? Visit our Q&A Community and ask the experts!
|
|
|
|
Let us know how we can update this page
(Click for more details)
|
|
We strive for accurate content and locality information. If you feel any of the content is incorrect, or if you feel we are missing vital locality information, please fill out the form below so we can update the site. If you are requesting a locality be added, please only include significant locality occurences for the mineral.
|
 |
| |
 |
|
|
|
|
|
