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Delhayelite

A valid IMA mineral species
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04944330017271922449695.jpg
Delhayelite, etc.

Rasvumchorr Mt, Murmansk Oblast, Russia
00089420017271922476346.jpg
Delhayelite, etc.

Kirovskii apatite mine, Kukisvumchorr Mt, Murmansk Oblast, Russia
01464330017271922509021.jpg
Delhayelite

Yukspor Mountain, Murmansk Oblast, Russia
04944330017271922449695.jpg
Delhayelite, etc.

Rasvumchorr Mt, Murmansk Oblast, Russia
00089420017271922476346.jpg
Delhayelite, etc.

Kirovskii apatite mine, Kukisvumchorr Mt, Murmansk Oblast, Russia
01464330017271922509021.jpg
Delhayelite

Yukspor Mountain, Murmansk Oblast, Russia
09167790017271922527152.jpg
Delhayelite, etc.

Rasvumchorr Mt, Murmansk Oblast, Russia
00089420017271922476346.jpg
Delhayelite, etc.

Kirovskii apatite mine, Kukisvumchorr Mt, Murmansk Oblast, Russia
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About DelhayeliteHide

Formula:
(Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 · 18H2O
Colour:
Colourless; Silver-grey, Greenish-grey
Specific Gravity:
2.60
Crystal System:
Orthorhombic
Member of:
Rhodesite Group
Name:
Named in 1959 by Th. G. Sahama and K. Hytönen after Fernand Delhaye (Clermont-Ferrand February 4 1880 - Saint-Gillis (Brussels) December 15 1946), of Belgian nationality. He worked in Central Africa.
Easily hydrothermally altered to hydrodelhayelite. Chemically somewhat similar to steudelite and sacrofanite.


Unique IdentifiersHide

Mindat ID:
1251
Long-form identifier:
mindat:1:1:1251:1

IMA Classification of DelhayeliteHide

Classification of DelhayeliteHide

Strunz-mindat (2026):
9.EB.10

9 : SILICATES (Germanates)
E : Phyllosilicates
B : Double nets with 4- and 6-membered rings
Dana 8th ed.:
72.5.1.4

72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
5 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with corrugated and complex layers
Hey's CIM Ref.:
17.10.9

17 : Silicates Containing other Anions
10 : Silicates with sulphate, molybdate or tungstate

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
DhyIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of DelhayeliteHide

Transparency:
Translucent
Colour:
Colourless; Silver-grey, Greenish-grey
Cleavage:
Distinct/Good
Parallel to (010)
Density:
2.60(3) g/cm3 (Measured)    2.50 g/cm3 (Calculated)

Optical Data of DelhayeliteHide

Type:
Biaxial (-)
RI values:
nα = 1.530 - 1.532 nβ = 1.532(2) nγ = 1.5326 - 1.533
2V:
Measured: 83° (3), Calculated: 83°
Birefringence:
observed birefringence is 0.002-0.003; reported α, β, and γ all given as ≈1.532; the calculated birefringence from having these values all assigned as 1.532 yields δ=0.000, which is not quite correct. Hence, α and γ were slightly adjusted (3rd and 4th decimal place, still within measured errors) to give the correct birefringence and measured 2V°.
Max. Birefringence:
δ = 0.001 - 0.003
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.

Surface Relief:
None to Very Low
Relative to Canada balsam mounting medium (n ≈ 1.537).

This shows the grain boundary and Becke line effect under plane-polarised light, based on the contrast between this mineral's average refractive index and the mounting medium. It does not take into account mineral colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure - the conoscopic view for a grain cut perpendicular to the acute bisectrix, using this mineral's 2V. The two small white dots mark the melatopes - the points where the two optic axes emerge - and are shown only when they fall within the field of view. The coloured bands are isochromatics, and the dark bands are isogyres.

Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
weak
Pleochroism:
Non-pleochroic
Comments:
nominally colorless, but sections cut perpendicular to [010] may show an anomalous bluish-gray color.
Comments:
X=a, Y=c, Z=b

Chemistry of DelhayeliteHide

Mindat Formula:
(Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 · 18H2O
Element Weights:
Element% weight
O47.401 %
Si27.170 %
Na6.950 %
Cl6.431 %
Ca6.058 %
Al4.894 %
H1.097 %

Calculated from ideal end-member formula.
O
Si
Na
Cl
Ca
Al
H
Elements listed:
Al, Ca, Cl, F, H, K, Na, O, S, Si - search for minerals with similar chemistry
Common Impurities:
Ti,Fe,Mn,Mg

Crystallography of DelhayeliteHide

Crystal System:
Orthorhombic
Cell Parameters:
a = 13.06 Å, b = 24.65 Å, c = 7.04 Å
Ratio:
a:b:c = 0.53 : 1 : 0.286
Unit Cell V:
2,266.38 ų (Calculated from Unit Cell)
Z:
1
Morphology:
platy
Comment:
Point Group: 2/m 2/m 2/m or mm2; Space Group: Pmmn or Pmn21

Crystal StructureHide

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IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0015364DelhayeliteCannillo E, Rossi G, Ungaretti L (1970) The crystal structure of delhayelite Rendiconti della Societa Italiana di Mineralogia e Petrologia 26 63-7519700293
CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
3.078 Å(100)
12.3 Å(35)
6.158 Å(25)
3.482 Å(10)
2.961 Å(5)
2.788 Å(5)
1.760 Å(5)

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Stage 4b: Highly evolved igneous rocks>3.0
35 : Ultra-alkali and agpaitic igneous rocks

Type Occurrence of DelhayeliteHide

Other Language Names for DelhayeliteHide

Relationship of Delhayelite to other SpeciesHide

Member of:
Rhodesite Group
Other Members of Rhodesite Group:
FivegiteK4Ca2[AlSi7O17(O2-xOHx)][(H2O)2-xOHx]ClOrth. mm2 : Pmn21
HydrodelhayeliteKCa2AlSi7O17(OH)2 · 6H2OOrth. mm2
MelansoniteNa◻KZrSi8O19 · 5H2OOrth. mmm(2/m2/m2/m) : Pmma
Monteregianite-(Y)(Na,K)6(Y,Ca)2Si16O38 · 10H2OMon. 2/m
NatromelansoniteNa3Zr[Si7AlO19] · 4H2OMon. 2/m : P21/m
RhodesiteKHCa2Si8O19 · 5H2OOrth. mmm(2/m2/m2/m)

Common AssociatesHide

Associations Based on Photo Data:
10 photos of Delhayelite associated with AegirineNaFe3+Si2O6
3 photos of Delhayelite associated with Fenaksite(K,Na)4(Fe,Mn)2(Si4O10)2(OH,F)
3 photos of Delhayelite associated with HisingeriteFe3+2(Si2O5)(OH)4 · 2H2O
2 photos of Delhayelite associated with MicroclineK(AlSi3O8)
2 photos of Delhayelite associated with EudialyteNa15Ca6Fe3Zr3Si(Si25O73)(O,OH,H2O)3(Cl,OH)2
1 photo of Delhayelite associated with FivegiteK4Ca2[AlSi7O17(O2-xOHx)][(H2O)2-xOHx]Cl
1 photo of Delhayelite associated with Lamprophyllite(Na,Mn2+)3(Sr,Na)2(Ti,Fe3+)3(Si2O7)2O2(OH,O,F)2
1 photo of Delhayelite associated with CanasiteK3Na3Ca5Si12O30(OH)4
1 photo of Delhayelite associated with VilliaumiteNaF
1 photo of Delhayelite associated with TitaniteCaTiO(SiO4)

Related Minerals - Strunz-mindat GroupingHide

9.EB.NatromelansoniteNa3Zr[Si7AlO19] · 4H2OMon. 2/m : P21/m
9.EB.05MelansoniteNa◻KZrSi8O19 · 5H2OOrth. mmm(2/m2/m2/m) : Pmma
9.EB.05RhodesiteKHCa2Si8O19 · 5H2OOrth. mmm(2/m2/m2/m)
9.EB.05MacdonalditeBaCa4Si16O36(OH)2 · 10H2OOrth.
9.EB.10HydrodelhayeliteKCa2AlSi7O17(OH)2 · 6H2OOrth. mm2
9.EB.15Monteregianite-(Y)(Na,K)6(Y,Ca)2Si16O38 · 10H2OMon. 2/m
9.EB.20CarletoniteKNa4Ca4Si8O18(CO3)4(OH,F) · H2OTet. 4/mmm(4/m2/m2/m) : P4/mbm
9.EB.20FluorcarletoniteKNa4Ca4Si8O18(CO3)4F · H2OTet.
9.EB.25Günterblassite(K,Ca,Ba)2(Fe,Ca,Mg,Na)[(Si,Al)13O25(OH)4] · 7H2O · Orth. mm2 : Pmn21
9.EB.25Hillesheimite(K,Ca,Ba,◻)2(Mg,Fe,Ca,◻)2[(Si,Al )13O23(OH)6](OH) · 8H2OOrth. mmm(2/m2/m2/m) : Pmmn
9.EB.25UmbrianiteK7Na2Ca2[Al3Si10O29]F2Cl2 Orth. mmm(2/m2/m2/m) : Pmmn
9.EB.30FivegiteK4Ca2[AlSi7O17(O2-xOHx)][(H2O)2-xOHx]ClOrth. mm2 : Pmn21

Fluorescence of DelhayeliteHide

In UV light:
Orange (from Khibiny, Russia)

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.

Internet Links for DelhayeliteHide

References for DelhayeliteHide

Localities for DelhayeliteHide

Showing 14 localities.

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.
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Locality ListHide

- 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.
DR Congo
 
  • North Kivu
    • Nyiragongo Territory
Richard +15 other references
Mineralogical Magazine (1959)
Italy
 
  • Umbria
    • Terni Province
      • San Venanzo
Sabatini (1899) +8 other references
Morocco
 
Berger et al. (2009)
Russia
 
  • Murmansk Oblast
Pekov (1998)
Yakovenchuk et al. (2005)
[World of Stones 95:5-6
Pekov (1998)
Arzamastsev et al. (2008) +1 other reference
Pekov (1998) +1 other reference
      • Rasvumchorr Mine
Pavel Kartashov specimens. +3 other references
Pekov (1998)
Khomyakov et al. (1983) +1 other reference
Tanzania
 
  • Arusha region
    • Ngorongoro District
Dawson (1998)
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