May 28 2014
Tvedalite is an orthorhombic mineral, containing silicon, oxygen, manganese, hydrogen, calcium, and beryllium. It was first observed in Vevja larvikite quarry, Tvedalen, Brunlanes, Vestfold Co. Norway. It was named after its discovery locality.
Properties of Tvedalite
The following are the key properties of Tvedalite:
- Cell Data
- Space Group: C-centered
- a = 8.724(6)
- b = 23.14(1)
- c = 4.923(4)
- Z = 2
- Crystal Data
- Orthorhombic
- Point Group: n.d
- As spherulites of platy crystals, up to 3mm, always incrusted with chiavennite
- X-ray Powder Pattern: 2.837 (100), 11.6 (93), 3.87 (75), 2.889 (75), 3.16 (74), 5.80 (68), 2.494 (58)
- Chemical Composition
| Elements |
Content 1 |
| SiO2 |
45 |
| CaO |
18.44 |
| H2O |
11.8 |
| MnO |
11.56 |
| BeO |
10.69 |
| FeO |
1.11 |
| Al2O3 |
0.68 |
| Total |
99.28 |
- Optical Properties
- Optical Class: Biaxial
- n = 1.604
- Estimated Properties
| Electron density |
Bulk density (electron density) = 2.56 g/cm3
note: Specific gravity of Tvedalite = 2.56 g/cm3 |
| Photoelectric |
PETvedalite = 4.61 barns/electron
U = PETvedalite x ρElectron density = 11.81 barns/cm3 |
| Fermion index |
Fermion index = 0.04
Boson index = 0.96 |
Radioactivity
|
Tvedalite is not radioactive
|
How to Identify Tvedalite
Tvedalite can be found in beige, pale gray or white color, with perfect cleavage. It has a transparent appearance, vitreous luster, and white streak.
The relative hardness of tvedalite is 4.5, and its density is 2.54 g/cm3.
Global Distribution
Tvedalite is widely distributed in the Vevja quarry, Tvedalen, Norway.
Occurrence of Tvedalite and Useful Mineral Association
Tvedalite occurs in nepheline syenite pegmatite, and is closely associated with minerals such as molybdenite, magnetite, fluorite, todorokite, chlorite, calcite, albite, epididymite, leucophanite, bastnasite-(Ce), parisite-(Ce), natrolite, analcime, and chiavennite.
References