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Groatite

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Formula:
NaCaMn
 
2
(PO
 
4
)(HPO
 
4
)
 
2
System:MonoclinicColour:Colourless to pale yellow
Hardness:3
Member of:Alluaudite Group
Name:
Named in honor of Lee A. Groat, Professor of Mineralogy at the University of British Columbia in Vancouver.

Classification of Groatite

IMA status:Approved 2008
Nickel-Strunz 10th (pending) edition ID:8.AC.10

8 : PHOSPHATES, ARSENATES, VANADATES
A : Phosphates, etc. without additional anions, without H2O
C : With medium-sized and large cations
Dana 8th edition ID:39.2.7.6

39 : HYDRATED ACID PHOSPHATES,ARSENATES AND VANADATES
2 : (AB)5[HXO4]2[XO4]2.xH2O
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Type Occurrence of Groatite

Type Locality:Tanco Mine (Bernic Lake Mine), Bernic Lake, Lac-du-Bonnet area, Manitoba, Canada
General Appearance of Type Material:Slightly divergent sprays of acicular crystals on whitlockite; stellate sprays embedded in whitlockite and an unidentified Na–Al phosphate; tabular mass of densely intergrown acicular crystals.
Place of Conservation of Type Material:Department of Natural History, Royal Ontario Museum, Toronto, Ontario, Canada (catalogue number M40501).
Geological Setting of type material:In a vug in a single 5–10 cm mass of phosphate–carbonate mineralization in a spodumene-rich boulder.
Associated Minerals at type locality:
QuartzCrandalliteWhitlockite

Physical Properties of Groatite

Lustre:Vitreous
Diaphaneity (Transparency):Translucent
Colour:Colourless to pale yellow
Comment:Pale orange, where massive
Streak:White
Hardness (Mohs):3
Tenacity:Brittle
Cleavage:None Observed
Crystals are too small in cross-section to observe cleavage.
Parting:None observed.
Fracture:Irregular/Uneven
Density (calculated):3.213 g/cm3

Crystallography of Groatite

Crystal System:Monoclinic
Class (H-M):2/m - Prismatic
Space Group:B2/b
Space Group Setting:C1 2/c 1
Cell Parameters:a = 12.5435(9) Å, b = 12.4324(9) Å, c = 6.7121(4) Å
β = 115.332(2)°
Ratio:a:b:c = 1.009 : 1 : 0.54
Unit Cell Volume:V 946.07 ų
Z:4
Twinning:None observed.
X-Ray Powder Diffraction:
d-spacingIntensity
6.204 (80)
5.653 (70)
3.608 (30)
3.187 (100)
2.788 (80)
2.726 (90)
2.580 (70)
2.185 (30)

Optical Data of Groatite

Type:Biaxial (+)
RI values: nα = 1.622(1) nβ = 1.634(1) nγ = 1.663(1)
2V:Measured: 67° (1), Calculated: 66.5°
Birefringence:0.041
Maximum Birefringence:δ = 0.041

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Pleochroism:Non-pleochroic

Chemical Properties of Groatite

Formula:
NaCaMn
 
2
(PO
 
4
)(HPO
 
4
)
 
2
Simplified for copy/paste:NaCaMn2(PO4)(HPO4)2
Essential elements:Ca, H, Mn, Na, O, P
All elements listed in formula:Ca, H, Mn, Na, O, P
Analytical Data:Average of 4 electron-microprobe analyses; water content was calculated as two (OH) per formula unit.
P2O5 (46.66)
FeO (0.49)
MnO (29.31)
CaO (12.51)
Na2O (6.87)
H2O (3.93)
Total (99.77)
Empirical Formula:
Na
 
1.02
Ca
 
1.02
Mn
2+
1.90
Fe
 
0.03
P
 
3.02
O
 
12
H
 
2
Common Impurities:Fe

Relationship of Groatite to other Species

Member of:Alluaudite Group
Other Members of Group:

- +
Alluaudite
(Na,Ca)Mn
2+
 
(Fe
3+
 
,Mn
2+
 
,Fe
2+
 
,Mg)
 
2
(PO
 
4
)
 
3
Alluaudite-Ca□
 
4
Ca
 
4
Mn
2+
4
Fe
3+
8
(PO
 
4
)
 
12
Alluaudite-Na□
 
4
Na
 
4
Mn
2+
4
Fe
3+
8
(PO
 
4
)
 
12
Arseniopleite
NaCaMn
2+
 
(Mn
2+
 
,Mg)
 
2
(AsO
 
4
)
 
3
Bradaczekite
NaCu
 
4
(AsO
 
4
)
 
3
Canutite
NaMn
 
3
[AsO
 
4
][AsO
 
3
(OH)]
 
2
Caryinite
(Na,Pb)(Ca,Na)(Ca,Mn
2+
 
)(Mn
2+
 
,Mg,Fe
3+
 
)
 
2
(AsO
 
4
)
 
3
Erikapohlite
Cu
 
3
(Zn,Cu,Mg)
 
4
Ca
 
2
(AsO
 
4
)
 
6
·2H
 
2
O
Ferroalluaudite
(Na,Ca)Fe
2+
 
(Fe
3+
 
,Mn
2+
 
,Fe
2+
 
)
 
2
(PO
 
4
)
 
3
Ferroalluaudite-NaNa
Na
 
4
Na
 
4
Fe
2+
4
Fe
3+
8
(PO
 
4
)
 
12
Ferrohagendorfite
NaCaFe
2+
 
Fe
2+
2
(PO
 
4
)
 
3
Hagendorfite
NaCaMn
2+
 
Fe
2+
2
(PO
 
4
)
 
3
Hagendorfite-NaNa
Na, Mn, Fe, P, O, H (?)
Hagendorfite-Varulite Series
NaCaMn
2+
 
(Fe
2+
 
,Fe
3+
 
,Mg)
 
2
(PO
 
4
)
 
3
Hatertite
Na
 
2
(Ca,Na)(Fe
3+
 
,Cu)
 
2
(AsO
 
4
)
 
3
Johillerite
Na(Mg,Zn)
 
3
Cu(AsO
 
4
)
 
3
Keyite
Cu
2+
3
Zn
 
4
Cd
 
2
(AsO
 
4
)
 
6
· 2H
 
2
O
Maghagendorfite
(□,Na,)(Na,Ca,Fe
2+
 
)Mn(Mg,Fe
2+
 
,Fe
3+
 
)
 
3
(PO
 
4
)
 
3
Manitobaite
Na
 
16
Mn
2+
 
 
25
Al
 
8
(PO
 
4
)
 
30
Nickenichite
Na
 
0.8
Ca
 
0.4
Cu
 
0.4
(Mg,Fe)
 
3
(AsO
 
4
)
 
3
O'Danielite
Na(Zn,Mg)
 
3
H
 
2
(AsO
 
4
)
 
3
Varulite
NaCaMn
2+
 
Mn
2+
2
(PO
 
4
)
 
3
Yazganite
NaFe
3+
2
(Mg,Mn
2+
 
)(AsO
 
4
)
 
3
· H
 
2
O
Related Minerals - Nickel-Strunz Grouping):

- +
8.AC.05Howardevansite
NaCuFe
 
2
(VO
 
4
)
 
3
8.AC.10Alluaudite
(Na,Ca)Mn
2+
 
(Fe
3+
 
,Mn
2+
 
,Fe
2+
 
,Mg)
 
2
(PO
 
4
)
 
3
8.AC.10Arseniopleite
NaCaMn
2+
 
(Mn
2+
 
,Mg)
 
2
(AsO
 
4
)
 
3
8.AC.10Caryinite
(Na,Pb)(Ca,Na)(Ca,Mn
2+
 
)(Mn
2+
 
,Mg,Fe
3+
 
)
 
2
(AsO
 
4
)
 
3
8.AC.10Ferroalluaudite
(Na,Ca)Fe
2+
 
(Fe
3+
 
,Mn
2+
 
,Fe
2+
 
)
 
2
(PO
 
4
)
 
3
8.AC.10Hagendorfite
NaCaMn
2+
 
Fe
2+
2
(PO
 
4
)
 
3
8.AC.10Johillerite
Na(Mg,Zn)
 
3
Cu(AsO
 
4
)
 
3
8.AC.10Maghagendorfite
(□,Na,)(Na,Ca,Fe
2+
 
)Mn(Mg,Fe
2+
 
,Fe
3+
 
)
 
3
(PO
 
4
)
 
3
8.AC.10Nickenichite
Na
 
0.8
Ca
 
0.4
Cu
 
0.4
(Mg,Fe)
 
3
(AsO
 
4
)
 
3
8.AC.10Varulite
NaCaMn
2+
 
Mn
2+
2
(PO
 
4
)
 
3
8.AC.10Ferrohagendorfite
NaCaFe
2+
 
Fe
2+
2
(PO
 
4
)
 
3
8.AC.10Bradaczekite
NaCu
 
4
(AsO
 
4
)
 
3
8.AC.10Yazganite
NaFe
3+
2
(Mg,Mn
2+
 
)(AsO
 
4
)
 
3
· H
 
2
O
8.AC.15Bobfergusonite
Na
 
2
Mn
 
5
FeAl(PO
 
4
)
 
6
8.AC.15Ferrowyllieite
(Na,Ca,Mn)(Fe,Mn)(Fe,Fe,Mg)Al(PO
 
4
)
 
3
8.AC.15Qingheiite
NaMn
3+
 
Mg(Al,Fe
3+
 
)(PO
 
4
)
 
3
8.AC.15Rosemaryite
(Na,Ca,Mn)(Mn,Fe
2+
 
)(Fe
3+
 
,Mg)Al(PO
 
4
)
 
3
8.AC.15Wyllieite
(Na,Ca,Mn)(Mn,Fe)(Fe,Mg)Al(PO
 
4
)
 
3
8.AC.15Ferrorosemaryite
◻NaFe
2+
 
Fe
3+
 
Al(PO
 
4
)
 
3
8.AC.15Qingheiite-(Fe2+)
Na
 
2
Fe
2+
 
MgAl(PO
 
4
)
 
3
8.AC.18Manitobaite
Na
 
16
Mn
2+
 
 
25
Al
 
8
(PO
 
4
)
 
30
8.AC.20Marićite
NaFe
2+
 
(PO
 
4
)
8.AC.25Berzeliite
NaCa
 
2
(Mg,Mn
2+
 
)
 
2
(AsO
 
4
)
 
3
8.AC.25Manganberzeliite
(Ca,Na)
 
3
(Mn
2+
 
,Mg)
 
2
(AsO
 
4
)
 
3
8.AC.25Palenzonaite
(Ca,Na)
 
3
CaMn
2+
2
(VO
 
4
)
 
3
8.AC.25Schäferite
Ca
 
2
NaMg
 
2
(VO
 
4
)
 
3
8.AC.30Brianite
Na
 
2
CaMg(PO
 
4
)
 
2
8.AC.35Vitusite-(Ce)
Na
 
3
(Ce,La,Nd)(PO
 
4
)
 
2
8.AC.40Olgite
(Sr,Ba)(Na,Sr,REE)
 
2
Na(PO
 
4
)
 
2
8.AC.40Bario-olgite
(Ba,Sr)(Na,Sr,REE)
 
2
Na(PO
 
4
)
 
2
·
8.AC.45Strontiowhitlockite
Sr
 
9
Mg(PO
 
4
)
 
6
(HPO
 
4
)
8.AC.45Whitlockite
Ca
 
9
Mg(PO
 
4
)
 
6
(HPO
 
4
)
8.AC.45Merrillite
Ca
 
9
NaMg(PO
 
4
)
 
7
8.AC.45Tuite
Ca
 
3
(PO
 
4
)
 
2
8.AC.45Ferromerrillite
Ca
 
9
NaFe
2+
 
(PO
 
4
)
 
7
8.AC.45Bobdownsite
Ca
 
9
Mg(PO
 
4
)
 
6
(PO
 
3
F)
8.AC.50Chladniite
{Ca}{Na
 
8
}{Ca
 
4
Na
 
4
}{(Mg,Fe
2+
 
)
 
43
}(PO
 
4
)
 
36
8.AC.50Fillowite
{Mn
2+
 
}{Na
 
8
}{Ca
 
4
Na
 
4
}{(Mn
2+
 
,Fe
2+
 
)
 
43
}(PO
 
4
)
 
36
8.AC.50Johnsomervilleite
Na
 
10
Ca
 
6
Mg
 
18
Fe
 
25
(PO
 
4
)
 
36
8.AC.50Galileiite
{Fe
2+
 
}{Na
 
8
}{Fe
2+
4
Na
 
4
}{Fe
2+
43
}(PO
 
4
)
 
36
8.AC.50Stornesite-(Y)
{(Y, Ca)}{Na
 
6
 
2
}{(Ca,Na)
 
8
}{(Mg,Fe
2+
 
)
 
43
}(PO
 
4
)
 
36
8.AC.50Xenophyllite
Na
 
4
Fe
2+
7
(PO
 
4
)
 
6
8.AC.55Harrisonite
Ca(Fe
2+
 
,Mg)
 
6
(PO
 
4
)
 
2
(SiO
 
4
)
 
2
8.AC.60Kosnarite
KZr
 
2
(PO
 
4
)
 
3
8.AC.65Panethite
(Na,Ca)
 
2
(Mg,Fe
2+
 
)
 
2
(PO
 
4
)
 
2
8.AC.70Stanfieldite
Ca
 
7
Ca
 
2
Mg
 
9
(PO
 
4
)
 
12
8.AC.75Ronneburgite
K
 
2
MnV
 
4
O
 
12
8.AC.80Tillmannsite
(Ag
 
3
Hg)(VO
 
4
,AsO
 
4
)
8.AC.85Filatovite
K(Al,Zn)
 
2
(As,Si)
 
2
O
 
8

Other Names for Groatite

Synonyms:
IMA2008-054
Other Languages:

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Groatite

Reference List:

- +
Cooper, M.A. et al. (2009): Groatite, NaCaMn2+2(PO4)[PO3(OH)]2, a new mineral species of the alluaudite group from the Tanco pegmatite, Bernic Lake, Manitoba, Canada: description and crystal structure. Canadian Mineralogist 47, 1225-1235.

Internet Links for Groatite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
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  • Localities for Groatite

    The 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.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Canada
     
    • Manitoba
      • Lac-du-Bonnet area
        • Bernic Lake
    Can.Min.47,1225(2009)
    Mineral and/or Locality  
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    Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
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