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Macfallite

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Manganese Mine, Copper Harbor, Keweenaw Co., Michigan, USA
© T. Kennedy 2002

Show Macfallite Photos (17)



Formula:
Ca
 
2
(Mn
3+
 
,Al)
 
3
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
3
System:MonoclinicColour:Reddish-brown, maroon.
Lustre:SilkyHardness:5
Name:For US author and amateur mineralogist Russell Patterson MacFall (1903-1983).
This page provides mineralogical data about Macfallite.

Classification of Macfallite

IMA status:Approved 1974
Strunz 8th edition ID:8/C.24-10
Nickel-Strunz 10th (pending) edition ID:9.BG.15

9 : SILICATES (Germanates)
B : Sorosilicates
G : Sorosilicates with mixed SiO4 and Si2O7 groups; cations in octahedral [6] and greater coordination
Dana 8th edition ID:58.2.3.2

58 : SOROSILICATES Insular, Mixed, Single, and Larger Tetrahedral Groups
2 : Insular, Mixed, Single, and Larger Tetrahedral Groups with cations in [6] and higher coordination; single and double groups (n = 1, 2)
Hey's CIM Ref.:16.16.20

16 : Silicates Containing Aluminum and other Metals
16 : Aluminosilicates of Mn
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Type Occurrence of Macfallite

Type Locality:Manganese Mine, Copper Harbor, Keweenaw Co., Michigan, USA
Year of Discovery:1974

Physical Properties of Macfallite

Lustre:Silky
Colour:Reddish-brown, maroon.
Hardness (Mohs):5

Crystallography of Macfallite

Crystal System:Monoclinic
Cell Parameters:a = 10.23Å, b = 6.08Å, c = 8.97Å
β = 110.75°
Ratio:a:b:c = 1.683 : 1 : 1.475
Unit Cell Volume:V 521.73 ų (Calculated from Unit Cell)

Optical Data of Macfallite

Type:Biaxial (-)
RI values: nα = 1.773 - 1.775 nβ = 1.795 nγ = 1.810 - 1.815
2V:Measured: 86° , Calculated: 78° to 88°
Maximum Birefringence:δ = 0.037 - 0.040

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Very High
Dispersion:r < v medium

Chemical Properties of Macfallite

Formula:
Ca
 
2
(Mn
3+
 
,Al)
 
3
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
3
Essential elements:Ca, H, Mn, O, Si
All elements listed in formula:Al, Ca, H, Mn, O, Si
Common Impurities:Ti,Al,Fe,Cr,V,Cu,Mg,K,Na,H2O

Relationship of Macfallite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
9.BG.05bAllanite-(Ce)
{CaCe}{Al
 
2
Fe
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05bAllanite-(La)
{CaLa}{Al
 
2
Fe
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05bAllanite-(Y)
{CaY}{Al
 
2
Fe
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05aClinozoisite
{Ca
 
2
}{Al
 
3
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05bDissakisite-(Ce)
{CaCe}{Al
 
2
Mg}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Dollaseite-(Ce)
{CaCe}{MgAlMg}(Si
 
2
O
 
7
)(SiO
 
4
)(OH)F
9.BG.05aEpidote
{Ca
 
2
}{Al
 
2
Fe
3+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Epidote-(Pb)
{CaPb}{Al
 
2
Fe
3+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Khristovite-(Ce)
{CaCe}{MgAlMn
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)(OH)F
9.BG.05Mukhinite
{Ca
 
2
}{Al
 
2
V
3+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Piemontite
{Ca
 
2
}{Al
 
2
Mn
3+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Piemontite-(Sr)
{CaSr}{Al
 
2
Mn
3+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05bManganiandrosite-(La)
{Mn
2+
 
La}{Mn
3+
 
AlMn
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Tawmawite
{Ca
 
2
}{(Al,Fe
3+
 
,Cr)
 
3
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Manganipiemontite-(Sr)
{CaSr}{Mn
3+
 
AlMn
3+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05bFerriallanite-(Ce)
{CaCe}{Fe
3+
 
AlFe
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Clinozoisite-(Sr)
{CaSr}{Al
 
3
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Manganiandrosite-(Ce)
{(Mn
2+
 
,Ca)(Ce,REE)}{Mn
3+
 
AlMn
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Dissakisite-(La)
{CaLa}{Al
 
2
Mg}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Vanadoandrosite-(Ce)
{Mn
2+
 
Ce}{V
3+
 
AlMn
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Uedaite-(Ce)
{Mn
2+
 
Ce}{Al
 
2
Fe
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05Epidote-(Sr)
{CaSr}{Al
 
2
Fe
3+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05bAllanite-(Nd)
{CaNd}{Al
 
2
Fe
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05bFerriallanite-(La)
{CaLa}{Fe
3+
 
AlFe
2+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.05bÅskagenite-(Nd)
{Mn
2+
 
Nd}{Al
 
2
Fe
3+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O
 
2
9.BG.10Zoisite
{Ca
 
2
}{Al
 
3
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
9.BG.15Sursassite
Mn
2+
2
Al
 
3
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
3
9.BG.20Julgoldite-(Fe2+)
Ca
 
2
(Fe
2+
 
,Mg)(Fe
3+
 
,Al)
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
2
 · H
 
2
O
9.BG.20Okhotskite
Ca
 
2
(Mn
2+
 
,Mg)(Mn
3+
 
,Al,Fe
3+
 
)
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
2
 · H
 
2
O
9.BG.20Pumpellyite-(Fe2+)
Ca
 
2
Fe
2+
 
Al
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
2
 · H
 
2
O
9.BG.20Pumpellyite-(Fe3+)
Ca
 
2
(Fe
3+
 
,Mg,Fe
2+
 
)(Al,Fe
3+
 
)
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH,O)
 
2
 · H
 
2
O
9.BG.20Pumpellyite-(Mg)
Ca
 
2
MgAl
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
2
 · H
 
2
O
9.BG.20Pumpellyite-(Mn2+)
Ca
 
2
(Mn
2+
 
,Mg)(Al,Mn
3+
 
,Fe
3+
 
)
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
2
 · H
 
2
O
9.BG.20Shuiskite
Ca
 
2
(Mg,Al)(Cr,Al)
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
2
 · 2H
 
2
O
9.BG.20Julgoldite-(Fe3+)
Ca
 
2
(Fe
3+
 
,Mg)(Fe
3+
 
,Al)
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH,O)
 
2
 · H
 
2
O
9.BG.20Pumpellyite-(Al)
Ca
 
2
(Al,Fe
2+
 
,Mg)Al
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH,O)
 
2
 · H
 
2
O
9.BG.20Poppiite
Ca
 
2
(V
3+
 
,Fe
3+
 
,Mg)(V
3+
 
,Al)
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH,O)
 
2
 · H
 
2
O
9.BG.20Julgoldite-(Mg)
Ca
 
2
(Mg,Fe
2+
 
)(Fe
3+
 
,Al)
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
2
 · H
 
2
O
9.BG.25Ganomalite
Pb
 
9
Ca
 
5
Mn(Si
 
2
O
 
7
)
 
4
(SiO
 
4
)O
9.BG.30Rustumite
Ca
 
10
(Si
 
2
O
 
7
)
 
2
(SiO
 
4
)(OH)
 
2
Cl
 
2
9.BG.35Vesuvianite
(Ca,Na,☐)
 
19
(Al,Mg,Fe
3+
 
)
 
13
(☐,B,Al,Fe
3+
 
)
 
5
(Si
 
2
O
 
7
)
 
4
(SiO
 
4
)
 
10
(OH,F,O)
 
10
9.BG.35Wiluite
Ca
 
19
(Al,Mg)
 
13
(B,☐,Al)
 
5
(Si
 
2
O
 
7
)
 
4
(SiO
 
4
)
 
10
(O,OH)
 
10
9.BG.35Manganvesuvianite
Ca
 
19
Mn
3+
 
(Al,Mn
3+
 
,Fe
3+
 
)
 
10
(Mg,Mn
2+
 
)
 
2
(Si
 
2
O
 
7
)
 
4
(SiO
 
4
)
 
10
O(OH)
 
9
9.BG.35Fluorvesuvianite
Ca
 
19
(Al,Mg,Fe
2+
 
)
 
13
(Si
 
2
O
 
7
)
 
4
(SiO
 
4
)
 
10
O(F,OH)
 
9
9.BG.40Vyuntspakhkite-(Y)
(Y,Yb)
 
4
Al
 
2.5-1.5
(Si,Al)
 
1.5-2.5
(SiO
 
4
)
 
4
O(OH)
 
7
9.BG.45Dellaite
Ca
 
6
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
2
9.BG.50Gatelite-(Ce)
CaCe
 
3
Al
 
2
(Al,Mg)(Mg,Fe
2+
 
,Al)(Si
 
2
O
 
7
)(SiO
 
4
)
 
3
(O,F)(OH,O)
 
2
9.BG.55Västmanlandite-(Ce)
Ca(Ce,La)
 
3
Al
 
2
Mg
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)
 
3
(OH)
 
2
F
Related Minerals - Hey's Index Grouping:

- +
16.16.1Kanonaite
Mn
3+
 
Al(SiO
 
4
)O
16.16.2Spessartine
Mn
2+
3
Al
 
2
(SiO
 
4
)
 
3
16.16.3Davreuxite
MnAl
 
6
Si
 
4
O
 
17
(OH)
 
2
16.16.4Sursassite
Mn
2+
2
Al
 
3
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
3
16.16.5Carpholite
Mn
2+
 
Al
 
2
(Si
 
2
O
 
6
)(OH)
 
4
16.16.6Kellyite
Mn
2+
2
Al(AlSiO
 
5
)(OH)
 
4
16.16.7Pennantite
Mn
2+
5
Al(AlSi
 
3
O
 
10
)(OH)
 
8
16.16.8Akatoreite
(Mn
2+
 
,Fe
2+
 
)
 
9
Al
 
2
(HSi
 
4
O
 
13
)
 
2
(OH)
 
6
16.16.9Ganophyllite
(K,Na,Ca)
 
2
Mn
 
8
(Si,Al)
 
12
(O,OH)
 
32
 · 8H
 
2
O
16.16.10Mangano-arfvedsonite
[Na][Na
 
2
][Mn
2+
4
(Fe
3+
 
)]Si
 
8
O
 
22
(OH)
 
2
16.16.11Masutomilite
(K,Rb)(Li,Mn
3+
 
,Al)
 
3
(AlSi
 
3
O
 
10
)(F,OH)
 
2
16.16.13Howieite
Na(Fe,Mn)
 
10
(Fe,Al)
 
2
Si
 
12
O
 
31
(OH)
 
13
16.16.14Eggletonite
(Na,K,Ca)
 
2
(Mn,Fe)
 
8
(Si,Al)
 
12
O
 
29
(OH)
 
7
 · 11H
 
2
O
16.16.15Bannisterite
Ca
 
0.5
(K,Na)
 
0.5
(Mn,Fe,Zn)
 
10
(Si,Al)
 
16
O
 
38
(OH)
 
8
 · 5.5H
 
2
O
16.16.16Taneyamalite
(Na,Ca)(Mn,Mg,Fe)
 
12
Si
 
12
(O,OH)
 
44
16.16.17Zussmanite
K(Fe,Mg,Mn)
 
13
(Si,Al)
 
18
O
 
42
(OH)
 
14
16.16.18Coombsite
K(Mn,Fe,Mg)
 
13
(Si,Al)
 
18
O
 
42
(OH)
 
14
16.16.19Henritermierite
Ca
 
3
(Mn
3+
 
,Al)
 
2
(SiO
 
4
)
 
2
(OH)
 
4
16.16.21Ottrélite
(Mn
2+
 
,Fe
2+
 
,Mg)Al
 
2
(SiO
 
4
)O(OH)
 
2
16.16.22Piemontite
{Ca
 
2
}{Al
 
2
Mn
3+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
16.16.23Okhotskite
Ca
 
2
(Mn
2+
 
,Mg)(Mn
3+
 
,Al,Fe
3+
 
)
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
2
 · H
 
2
O
16.16.24Pumpellyite-(Mn2+)
Ca
 
2
(Mn
2+
 
,Mg)(Al,Mn
3+
 
,Fe
3+
 
)
 
2
(Si
 
2
O
 
7
)(SiO
 
4
)(OH)
 
2
 · H
 
2
O
16.16.25Piemontite-(Sr)
{CaSr}{Al
 
2
Mn
3+
 
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)

Other Names for Macfallite

Synonyms:
IMA1974-057
Other Languages:
German:Macfallit
Russian:Макфаллит
Spanish:Macfallita

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 Macfallite

Reference List:

- +
Moore, P.B., Ito, J., and Steele, I.M. (1979) Macfallite and orientite: calcium manganese (III) silicates from upper Michigan. Mineralogical Magazine: 43: 325-331.

American Mineralogist (1980): 65: 406.

Moore, P.B., J. Shen, and T. Araki (1985) Crystal chemistry of the 2∞[M 3+ 2ф2(TO4)2] sheet: structural principles and crystal structures of ruizite, macfallite and orientite. American Mineralogist (1985): 70: 171-181.

Neues Jahrbuch für Mineralogie, Monatshefte (1989): 455.

Nagashima, Mariko; Rahmoun, Nouri-Said; Alekseev, Evgeny V.; Geiger, Charles A.; Armbruster, Thomas; Akasaka, Masahide (2008): Crystal chemistry of macfallite: relationships to sursassite and pumpellyite. American Mineralogist 93, 1851-1857.

Internet Links for Macfallite

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    • Localities for Macfallite

    Hide Locality List
    (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.
    Italy
     
    • Liguria
      • La Spezia Province
        • Vara Valley
          • Borghetto Vara
    		Palenzona A. (1990) - Orientite e MacFallite di Cerchiara (La Spezia) - Rivista Mineralogica Italiana, Milano, Fasc. 2, pp111-114
    Japan
     
    • Hokkaido
      • Okhotsk Subprefecture (Abashiri Province)
        • Tokoro-gun
    		Miyajima, N., Osawa, S., Miura, H., Kikuchi, T. and Hiriya, Yu (1994) Proceedings of the 9th Quadrennial International Association on the Genesis of Ore Deposits (IAGOD) Symposium (Beijing), 603-616.
    USA
     
    • Michigan
      • Keweenaw Co.
        • Copper Harbor
    		[Nickel & Nichols, 1991 - "Mineral Reference Manual", p124]
    Mineral and/or Locality
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