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About LoudouniteHide

NaCa5Zr4Si16O40(OH)11 · 8H2O
Light green to white
Specific Gravity:
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.
This page provides mineralogical data about Loudounite.

Classification of LoudouniteHide

Approval Year:
First Published:
Approval History:

9 : SILICATES (Germanates)
H : Unclassified silicates
F : With Nb, Ta, Zr

59 : CYCLOSILICATES Three-Membered Rings
2 : Three-Membered Rings, hydrated

Physical Properties of LoudouniteHide

Light green to white
None Observed
2.48 g/cm3 (Measured)    
Measured using heavy liquids

Optical Data of LoudouniteHide

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.
Surface Relief:
r > v weak

Chemical Properties of LoudouniteHide

NaCa5Zr4Si16O40(OH)11 · 8H2O
Common Impurities:

X-Ray Powder DiffractionHide

Powder Diffraction Data:
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)

Type Occurrence of LoudouniteHide

General Appearance of Type Material:
Colorles spherules
Place of Conservation of Type Material:
Smithsonian Institution, NMNH 14939.
Geological Setting of Type Material:
Triassic diabase
Dunn P J, Newbury D (1983) Loudounite, a new zirconium silicate from Virginia, The Canadian Mineralogist 21, 37-40

Synonyms of LoudouniteHide

Other Language Names for LoudouniteHide


Related Minerals - Nickel-Strunz GroupingHide

9.HF.05MongoliteCa4Nb6Si5O24(OH)10 · nH2OTet.

Related Minerals - Dana Grouping (8th Ed.)Hide · 2H2OMon. · 2H2O · 2H2OOrth. mmm (2/m 2/m 2/m) : Pmna[Si3O9] · 2H2OOrth. mm2

Fluorescence of LoudouniteHide

None observed

Other InformationHide

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 LoudouniteHide

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 LoudouniteHide

Localities for LoudouniteHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for 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 (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
  • Virginia
    • Fairfax Co.
      • Culpeper Basin
        • Centreville
Minerals of Virginia, 1990 by R. V. Dietrich; Canadian Mineralogist(1983) 21, 37-40
    • Loudoun Co.
      • Leesburg
Canadian Mineralogist(1983) 21, 37-40; Rocks & Min.:60:167.
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