Loudounite
A valid IMA mineral species
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About Loudounite
Seal of Loudoun County, Virginia, USA
Formula:
NaCa5Zr4Si16O40(OH)11 · 8H2O
Colour:
Light green to white
Hardness:
5
Specific Gravity:
2.48
Name:
Named by Pete J. Dunn and Dale Newbury in 1982 for Loudoun County, Virginia, that includes the type locality.
The pronounciation is LOWD-ən-ite, where the first syllable rhymes with PROUD.
The pronounciation is LOWD-ən-ite, where the first syllable rhymes with PROUD.
This page provides mineralogical data about Loudounite.
Unique Identifiers
Mindat ID:
2440
Long-form identifier:
mindat:1:1:2440:8
Similar Names
IMA Classification of Loudounite
Approved
IMA Formula:
NaCa5Zr4+4Si16O40(OH)11·8H2O
Approval year:
1982
First published:
1983
Approval history:
IMA1982-013
Classification of Loudounite
9.HF.10
9 : SILICATES (Germanates)
H : Unclassified silicates
F : With Nb, Ta, Zr
9 : SILICATES (Germanates)
H : Unclassified silicates
F : With Nb, Ta, Zr
59.2.2.5
59 : CYCLOSILICATES Three-Membered Rings
2 : Three-Membered Rings, hydrated
59 : CYCLOSILICATES Three-Membered Rings
2 : Three-Membered Rings, hydrated
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 for Standard |
|---|---|---|
| Ldo | 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 Loudounite
Transparency:
Transparent
Colour:
Light green to white
Streak:
White
Hardness:
5 on Mohs scale
Cleavage:
None Observed
Density:
2.48(3) g/cm3 (Measured)
Comment:
Measured using heavy liquids
Optical Data of Loudounite
Type:
Biaxial
RI values:
nα = 1.536(4) nγ = 1.550(4)
Max. Birefringence:
δ = 0.014
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate
Dispersion:
r > v weak
Chemistry of Loudounite
Mindat Formula:
NaCa5Zr4Si16O40(OH)11 · 8H2O
Element Weights:
Common Impurities:
Fe,Al,Mn,Mg,K
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.37 Å | (60) |
| 5.81 Å | (50) |
| 4.56 Å | (30) |
| 4.06 Å | (70) |
| 3.527 Å | (40) |
| 2.931 Å | (100) |
| 2.694 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] |
Type Occurrence of Loudounite
General Appearance of Type Material:
Green to colorless spherules, typically 0.05 mm in diameter and exceptionally to 0.1 mm. In the type material they were all coated in ancylite.
Place of Conservation of Type Material:
National Museum of Natural History (Smithsonian), Washington, D.C., USA, 149397.
Geological Setting of Type Material:
Triassic diabase.
Associated Minerals at Type Locality:
Synonyms of Loudounite
Other Language Names for Loudounite
Common Associates
Associations Based on Photo Data:
| 2 photos of Loudounite associated with Albite | Na(AlSi3O8) |
| 1 photo of Loudounite associated with Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| 1 photo of Loudounite associated with Chlorite Group | |
| 1 photo of Loudounite associated with 'Byssolite' | AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| 1 photo of Loudounite associated with Stilbite Subgroup | M6-7[Al8-9Si27-28O72] · nH2O |
Related Minerals - Strunz-mindat Grouping
| 9.HF.05 | Mongolite | Ca4Nb6Si5O24(OH)10 · nH2O |
Fluorescence of Loudounite
None observed
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 Loudounite
mindat.org URL:
https://www.mindat.org/min-2440.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Loudounite
Localities for Loudounite
Showing 4 localities.
symbol to view information about a locality.
The 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).
All localities listed without proper references should be considered as questionable.
Norway | |
| Larsen (2021) |
| Larsen (2021) |
USA | |
| Dunn et al. (1983) +1 other reference |
| Rocks & Min.:60:167. +1 other reference |
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New Goose Creek Quarry, Leesburg, Loudoun County, Virginia, USA