Loudounite
This page is currently not sponsored. Click here to sponsor this page.
About Loudounite
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.
Classification of Loudounite
Approved
Approval Year:
1982
First Published:
1983
Approval History:
IMA1982-013
8/G.09-20
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
Physical Properties of Loudounite
Colour:
Light green to white
Streak:
White
Hardness:
5 on Mohs scale
Cleavage:
None Observed
Density:
2.48 g/cm3 (Measured)
Comment:
Measured using heavy liquids
Optical Data of Loudounite
Type:
Biaxial
RI values:
nα = 1.536 nγ = 1.550
Max Birefringence:
δ = 0.014

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r > v weak
Chemical Properties of Loudounite
Formula:
NaCa5Zr4Si16O40(OH)11 · 8H2O
Common Impurities:
Fe,Al,Mn,Mg,K
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
7.37 | (60) |
5.81 | (50) |
4.56 | (30) |
4.06 | (70) |
3.527 | (40) |
2.931 | (100) |
2.694 | (40) |
Type Occurrence of Loudounite
General Appearance of Type Material:
Colorles spherules
Place of Conservation of Type Material:
Smithsonian Institution, NMNH 14939.
Geological Setting of Type Material:
Triassic diabase
Reference:
Dunn P J, Newbury D (1983) Loudounite, a new zirconium silicate from Virginia, The Canadian Mineralogist 21, 37-40
Synonyms of Loudounite
Other Language Names for Loudounite
German:Loudounit
Spanish:Loudounita
Related Minerals - Nickel-Strunz Grouping
9.HF.05 | Mongolite | Ca4Nb6Si5O24(OH)10 · nH2O | Tet. |
Related Minerals - Dana Grouping (8th Ed.)
59.2.2.1 | Catapleiite | Na2Zr(Si3O9) · 2H2O | Mon. |
59.2.2.2 | Calciocatapleiite | CaZr(Si3O9) · 2H2O | |
59.2.2.3 | Gaidonnayite | Na2Zr(Si3O9) · 2H2O | Orth. mmm (2/m 2/m 2/m) : Pmna |
59.2.2.4 | Georgechaoite | NaKZr[Si3O9] · 2H2O | Orth. mm2 |
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.
References for Loudounite
Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Dunn, P.J., Newbury, D. (1983) Loudounite, a new zirconium silicate from Virginia. The Canadian Mineralogist: 21: 37-40.
Dunn, P.J., Grice, J.D., Fleischer, M., Pabst, A. (1983) New mineral names. American Mineralogist: 68: 1038-1041.
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.
Search Engines:
External Links:
Mineral Dealers:
Localities for Loudounite
Locality List




All localities listed without proper references should be considered as questionable.
USA | |
| Minerals of Virginia, 1990 by R. V. Dietrich; Canadian Mineralogist(1983) 21, 37-40 |
| Canadian Mineralogist(1983) 21, 37-40; Rocks & Min.:60:167. |
New Goose Creek Quarry, Leesburg, Loudoun Co., Virginia, USA