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About Monteregianite-(Y)Hide

(Na,K)6(Y,Ca)2Si16O38 · 10H2O
Colorless, white, grey, rarely mauve or pale green
Vitreous, Silky
Specific Gravity:
Crystal System:
Named by George Y. Chao in 1978 after the Monteregian Hills, a series of monadnocks or prominent hills on an otherwise flat landscape in eastern Quebec, Canada. The type locality for the mineral, Poudrette Quarry, Mont Saint-Hilaire, is on one of these hills.

Before being described, the mineral was referred to as UK-6 in Mont Saint-Hilaire related literature.
Monteregianite-(Y)-Wickenburgite Series.

Several synthetic REE analogues have been prepared.

Classification of Monteregianite-(Y)Hide

First Published:

9 : SILICATES (Germanates)
E : Phyllosilicates
B : Double nets with 4- and 6-membered rings

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

14 : Silicates not Containing Aluminum
8 : Silicates of Group III metals other than Al

Physical Properties of Monteregianite-(Y)Hide

Vitreous, Silky
Transparent, Translucent, Opaque
Colorless, white, grey, rarely mauve or pale green
3½ on Mohs scale
{010} perfect, {001} very good,{100} fair.
2.42 g/cm3 (Measured)    2.391 g/cm3 (Calculated)

Optical Data of Monteregianite-(Y)Hide

Biaxial (+)
RI values:
nα = 1.510 nβ = 1.513 nγ = 1.517
Max Birefringence:
δ = 0.007
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:

Chemical Properties of Monteregianite-(Y)Hide

(Na,K)6(Y,Ca)2Si16O38 · 10H2O
IMA Formula:
KNa2YSi8O19 · 5H2O

Crystallography of Monteregianite-(Y)Hide

Crystal System:
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 9.512(2) Å, b = 23.956(4) Å, c = 9.617(2) Å
β = 93.85(1)°
a:b:c = 0.397 : 1 : 0.401
Unit Cell V:
2,186.48 ų (Calculated from Unit Cell)
Bounded by {010}, {001} and {100}. Some also show {101}.
Space group P21/n.

X-Ray Powder DiffractionHide

Powder Diffraction Data:
12.00 (100)
7.03 (100)
6.55 (40)
6.02 (50)
4.42 (100)
3.405 (50)
3.026 (50)
2.873 (80)

Type Occurrence of Monteregianite-(Y)Hide

General Appearance of Type Material:
Needle-shaped crystals in radiating clusters and as groups of tabular crystals.
Place of Conservation of Type Material:
Canadian Museum of Nature, Ottawa, Canada, 37130.
National Museum of Natural History, Washington, D.C., USA, 145548.
Geological Setting of Type Material:
Miarolitic cavities and thermally metamorphosed inclusions and rheomorphic breccias in nepheline syenite.

Synonyms of Monteregianite-(Y)Hide

Other Language Names for Monteregianite-(Y)Hide

Relationship of Monteregianite-(Y) to other SpeciesHide

Common AssociatesHide

Associated Minerals Based on Photo Data:
Calcite11 photos of Monteregianite-(Y) associated with Calcite on mindat.org.
Quartz3 photos of Monteregianite-(Y) associated with Quartz on mindat.org.
Chabazite-Na2 photos of Monteregianite-(Y) associated with Chabazite-Na on mindat.org.
Aegirine1 photo of Monteregianite-(Y) associated with Aegirine on mindat.org.
Pectolite1 photo of Monteregianite-(Y) associated with Pectolite on mindat.org.
Albite1 photo of Monteregianite-(Y) associated with Albite on mindat.org.
Fluorite1 photo of Monteregianite-(Y) associated with Fluorite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

9.EB.05MacdonalditeBaCa4Si16O36(OH)2 · 10H2OOrth.
9.EB.05RhodesiteKHCa2Si8O19 · 5H2OOrth. mmm (2/m 2/m 2/m)
9.EB.10Delhayelite(Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 · 18H2OOrth.
9.EB.10HydrodelhayeliteKCa2AlSi7O17(OH)2 · 6H2OOrth.
9.EB.20CarletoniteKNa4Ca4Si8O18(CO3)4(OH,F) · H2OTet. 4/mmm (4/m 2/m 2/m) : P4/mbm

Related Minerals - Dana Grouping (8th Ed.)Hide · 5H2OOrth. mmm (2/m 2/m 2/m) · 10H2OOrth.,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 · 18H2OOrth. · 6H2OOrth.

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

14.8.3Keiviite-(Yb)Yb2Si2O7Mon. 2/m : B2/m
14.8.9Ashcroftine-(Y)K5Na5(Y,Ca)12Si28O70(OH)2(CO3)8 · 8H2OTet. 4/mmm (4/m 2/m 2/m) : I4/mmm
14.8.13Cerite-(Ce)(Ce,Ca)9(Mg,Fe)(SiO4)3(HSiO4)4(OH)3Trig. 3m : R3c
14.8.14CascanditeCa(Sc,Fe3+)(HSi3O9)Tric. 1

Other InformationHide

Thermal Behaviour:
Three distinct stages of dehydration at 25-80, 80-200, and 200-400 °C.
Readily etched by 1:l HCl, HNO3, and H2SO4.
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 Monteregianite-(Y)Hide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Chao, G.Y. (1978) Monteregianite, a new hydrous sodium potassium yttrium silicate mineral from Mont St-Hilaire, Québec. Canadian Mineralogist: 16: 561-565.
Fleischer, M., Pabst, A., Mandarino, J.A. (1980) New mineral names. American Mineralogist: 65: 205-210.
Ghose, S., Sen Gupta, P.K., Campana C.F. (1987) Symmetry and crystal structure of montregianite [sic], Na4K2Y2Si16O38²10H2O; a double-sheet silicate with zeolitic properties. American Mineralogist: 72: 365-374.
Mandarino, J.A., Anderson, V. (1989) Monteregian Treasures. Cambridge University Press 144-145.
Horváth, L., Gault, R.G. (1990) The mineralogy of Mont Saint Hilaire. Mineralogical Record: 21: 284 359.

Internet Links for Monteregianite-(Y)Hide

Localities for Monteregianite-(Y)Hide

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.
Canada (TL)
  • Québec
    • Montérégie
      • La Vallée-du-Richelieu RCM
        • Mont Saint-Hilaire
Chao G.Y. (1978), Monteregianite, a new hydrous sodium potassium yttrium silicate mineral from Mont St-Hilaire, Quebec. Canadian Mineralogist: 16: 561-565. HORVÁTH, L., and GAULT, R.G. (1990) The mineralogy of Mont Saint Hilaire. Mineralogical Record, 21, 284 359.
Mineral and/or Locality  
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