Tvedalite
A valid IMA mineral species
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About Tvedalite
Formula:
(Ca,Mn)4Be3Si6O17(OH)4 · 3H2O
Colour:
Creamy-white, light beige
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
2.541
Crystal System:
Orthorhombic
Name:
Named after its discovery locality, Vevja quarry, Tvedalen area, Vestfold, Norway.
Type Locality:
Unique Identifiers
Mindat ID:
4065
Long-form identifier:
mindat:1:1:4065:1
GUID
(UUID V4):
(UUID V4):
2e1979e0-7ad0-4218-8859-dc004c01ba9d
IMA Classification of Tvedalite
Classification of Tvedalite
9.DF.20
9 : SILICATES (Germanates)
D : Inosilicates
F : Inosilicates with 2-periodic multiple chains
9 : SILICATES (Germanates)
D : Inosilicates
F : Inosilicates with 2-periodic multiple chains
70.5.2.1
70 : INOSILICATES Column or Tube Structures
5 : Column or Tube Structures with chains linked by Be
70 : INOSILICATES Column or Tube Structures
5 : Column or Tube Structures with chains linked by Be
14.3.19
14 : Silicates not Containing Aluminum
3 : Silicates of Be
14 : Silicates not Containing Aluminum
3 : Silicates of Be
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Symbol | Source | Reference |
---|---|---|
Tve | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Tvedalite
Vitreous
Transparency:
Translucent
Colour:
Creamy-white, light beige
Streak:
White
Hardness:
4½ on Mohs scale
Hardness Data:
Estimated
Cleavage:
Perfect
{010}
{010}
Density:
2.541 g/cm3 (Measured) 2.554 g/cm3 (Calculated)
Optical Data of Tvedalite
Type:
Biaxial
Dispersion:
r > v
Chemistry of Tvedalite
Mindat Formula:
(Ca,Mn)4Be3Si6O17(OH)4 · 3H2O
Common Impurities:
Al,Fe
Crystallography of Tvedalite
Crystal System:
Orthorhombic
Cell Parameters:
a = 8.72 Å, b = 23.14 Å, c = 4.92 Å
Ratio:
a:b:c = 0.377 : 1 : 0.213
Unit Cell V:
992.76 ų (Calculated from Unit Cell)
Comment:
C-centered lattice, space group unknown
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
11.6 Å | (93) |
5.80 Å | (68) |
3.87 Å | (75) |
3.16 Å | (74) |
2.889 Å | (75) |
2.837 Å | (100) |
2.494 Å | (58) |
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 4b: Highly evolved igneous rocks | >3.0 |
35 : Ultra-alkali and agpaitic igneous rocks |
Type Occurrence of Tvedalite
General Appearance of Type Material:
Spherulites up to 3 mm in diameter composed of densely packed, radially oriented platelets (a few μm in length). The spherulites are overgrown by a crust of chiavennite.
Place of Conservation of Type Material:
University of Oslo, Oslo, Norway, 14770.
Geological Setting of Type Material:
In heavily zeolitized and hydrothermally parts of irregular nepheline syenite pegmatites.
Associated Minerals at Type Locality:
Synonyms of Tvedalite
Other Language Names for Tvedalite
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
9.DF. | Bohseite | Ca4Be3+xAl1-xSi9O25-x(OH)3+x |
9.DF.05 | Chesterite | (Mg,Fe)17Si20O54(OH)6 |
9.DF.05 | Clinojimthompsonite | (Mg,Fe)5Si6O16(OH)2 |
9.DF.05 | Jimthompsonite | (Mg,Fe)5Si6O16(OH)2 |
9.DF.15 | Ershovite | Na4K3(Fe,Mn,Ti)2Si8O22(OH)4 · 4H2O |
9.DF.15 | Paraershovite | Na3K3Fe3+2Si8O20(OH)4 · 4H2O |
9.DF.25 | Bavenite | Ca4Be2Al2Si9O26(OH)2 |
9.DF.30 | Bigcreekite | BaSi2O5 · 4H2O |
Fluorescence of Tvedalite
non-fluorescent
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Tvedalite
mindat.org URL:
https://www.mindat.org/min-4065.html
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Please feel free to link to this page.
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References for Tvedalite
Localities for Tvedalite
Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
Norway | |
| Larsen et al. (2005) |
| Nordrum (2002) +1 other reference |
Nordrum (2004) +1 other reference | |
| Grice et al. (2013) |
| Åsheim +3 other references |
Spain | |
| Dill et al. (2023) |
Dill et al. (2023) |
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Saga Pearl Quarry, Tvedalen, Larvik, Vestfold, Norway