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About SynadelphiteHide

Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O
Colourless (crystal centers), red to brown (exteriors), blackish; colourless to pale brown or reddish in transmitted light.
Adamantine, Vitreous, Sub-Metallic
Specific Gravity:
3.57 - 3.79
Crystal System:
Named in 1884 by Stens Anders Hjalmar Sjögren from Greek σύν = "syn" for "with," plus άδελφος = "adelphos," for "brother," alluding to its association with allactite and hematolite, several other chemically similar minerals.

Classification of SynadelphiteHide

Approved, 'Grandfathered' (first described prior to 1959)

B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1

5 : Hydrated Compound Phosphates, etc·, Containing Hydroxyl or Halogen

20 : Arsenates (also arsenates with phosphate, but without other anions)
8 : Arsenates of Mn

Physical Properties of SynadelphiteHide

Adamantine, Vitreous, Sub-Metallic
Transparent, Translucent, Opaque
Colourless material is vitreous, whereas the coloured material is adamantine to sub-metallic.
Colourless (crystal centers), red to brown (exteriors), blackish; colourless to pale brown or reddish in transmitted light.
4½ on Mohs scale
On {010}, imperfect.
Irregular/Uneven, Conchoidal
3.57 - 3.79 g/cm3 (Measured)    3.56 g/cm3 (Calculated)
Colourless material density is at or about the 3.57 value. Reddish plumbian material may go to 3.79 or higher. The calculated vlaue is for Långban material with colourless cores.

Optical Data of SynadelphiteHide

Biaxial (+)
RI values:
nα = 1.750 - 1.870 nβ = 1.751 - 1.880 nγ = 1.761 - 1.930
Measured: 37° to 40°, Calculated: 36° to 50°
Max Birefringence:
δ = 0.011 - 0.060
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Very High
r > v
X = Colourless or Light brown
Y = Colourless or Brown
Z = light brown or Dark red-brown

Colours are for the colourless material and the coloured material, respectively.

Chemical Properties of SynadelphiteHide

Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O
IMA Formula:
Mn2+9(AsO4)2(AsO3)(OH)9 · 2H2O

Crystallography of SynadelphiteHide

Crystal System:
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Cell Parameters:
a = 10.754(11) Å, b = 18.865(17) Å, c = 9.884(14) Å
a:b:c = 0.57 : 1 : 0.524
Unit Cell V:
2,005.21 ų (Calculated from Unit Cell)
Crystals short prismatic [001], with {110} striated [001]. Crystals viewed as seeming individuals are fourlings (the mineral was originally thought to be triclinic-pseudo-orthorhombic).
Fourlings twinned by reflection on (100) and (010) of a "pseudo-orthogonal triclinic" lattice (crystal-structure determination however showed orthorhombic symmetry). Massive; reniform crusts.
Originally thought to be triclinic-pseudo-orthorhombic.

X-Ray Powder DiffractionHide

Powder Diffraction Data:
9.36 (7)
8.72 (10)
5.27 (5)
3.080 (5)
2.636 (9)
2.091 (7)
1.5996 (7)

Type Occurrence of SynadelphiteHide

Synonyms of SynadelphiteHide

Other Language Names for SynadelphiteHide

Varieties of SynadelphiteHide

HemafibriteA blood-red and fibrous variety of Synadelphite.
PlumbosynadelphiteA superfluous name for plumbian synadelphite.

Relationship of Synadelphite to other SpeciesHide

Other Members of this group:
Hematolite(Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23Trig. 3 : R3
KraissliteZn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16Orth. 2 2 2 : C2 2 21
McgoverniteMn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21Trig. 3m (3 2/m)

Common AssociatesHide

Associated Minerals Based on Photo Data:
Calcite5 photos of Synadelphite associated with Calcite on mindat.org.
Hematolite3 photos of Synadelphite associated with Hematolite on mindat.org.
Magnetite1 photo of Synadelphite associated with Magnetite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

8.BE.05AugeliteAl2(PO4)(OH)3Mon. 2/m : B2/m
8.BE.10GrattarolaiteFe3+3(PO4)O3Trig. 3m : R3m
8.BE.15CornetiteCu3(PO4)(OH)3Orth. mmm (2/m 2/m 2/m) : Pbca
8.BE.20ClinoclaseCu3(AsO4)(OH)3Mon. 2/m : P21/b
8.BE.25ArhbariteCu2Mg(AsO4)(OH)3Tric. 1 : P1
8.BE.30AllactiteMn2+7(AsO4)2(OH)8Mon. 2/m : P21/b
8.BE.30FlinkiteMn2+2Mn3+(AsO4)(OH)4Orth. mmm (2/m 2/m 2/m)
8.BE.30RaadeiteMg7(PO4)2(OH)8Mon. 2/m
8.BE.30ArganditeMn7(VO4)2(OH)8Mon. 2/m : P21/m
8.BE.35Chlorophoenicite(Mn,Mg)3Zn2(AsO4)(OH,O)6Mon. 2/m : B2/m
8.BE.35Magnesiochlorophoenicite(Mg,Mn)3Zn2(AsO4)(OH,O)6Mon. 2/m : B2/m
8.BE.45Hematolite(Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23Trig. 3 : R3
8.BE.45KraissliteZn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16Orth. 2 2 2 : C2 2 21
8.BE.45McgoverniteMn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21Trig. 3m (3 2/m)
8.BE.45CarlfrancisiteMn2+3(Mn2+,Mg,Fe3+,Al)42[As3+O3]2(As5+O4)4[(Si,As5+)O4]6[(As5+,Si)O4]2(OH)42 Trig. 3m (3 2/m) : R3c
8.BE.55Holdenite(Mn2+,Mg)6Zn3(AsO4)2(SiO4)(OH)8Orth. mmm (2/m 2/m 2/m) : Ccca
8.BE.60KoliciteMn2+7Zn4(AsO4)2(SiO4)2(OH)8Orth. mmm (2/m 2/m 2/m) : Cmca
8.BE.65Sabelliite(Cu,Zn)2Zn(AsO4,SbO4)(OH)3Trig. 3 : P3
8.BE.70JarosewichiteMn2+3Mn3+(AsO4)(OH)6Orth. 2 2 2
8.BE.85WaterhouseiteMn2+7(PO4)2(OH)8Mon. 2/m : P21/b

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

20.8.1SarkiniteMn2+2(AsO4)(OH)Mon. 2/m : P2/m
20.8.2EveiteMn2+2(AsO4)(OH)Orth. mmm (2/m 2/m 2/m) : Pnnm
20.8.4FlinkiteMn2+2Mn3+(AsO4)(OH)4Orth. mmm (2/m 2/m 2/m)
20.8.5JarosewichiteMn2+3Mn3+(AsO4)(OH)6Orth. 2 2 2
20.8.6AllactiteMn2+7(AsO4)2(OH)8Mon. 2/m : P21/b
20.8.7KrautiteMn(HAsO4) · H2OMon. 2 : P21
20.8.9SterlinghilliteMn2+3(AsO4)2 · 3H2OTric. 1 : P1
20.8.10GeigeriteMn2+5(AsO4)2(HAsO4)2 · 10H2OTric.
20.8.11Akrochordite(Mn2+,Mg)5(AsO4)2(OH)4 · 4H2OMon. 2/m : P21/b
20.8.12Manganohörnesite(Mn,Mg)3(AsO4)2 · 8H2OMon. 2/m : P2/m
20.8.13FluckiteCaMn2+(HAsO4)2 · 2H2OTric. 1 : P1
20.8.14BrandtiteCa2Mn2+(AsO4)2 · 2H2OMon. 2/m : P21/b
20.8.15ParabrandtiteCa2Mn2+(AsO4)2 · 2H2OTric.
20.8.16WallkilldelliteCa2Mn2+3(AsO4)2(OH)4 · 9H2OHex.
20.8.17Berzeliite(NaCa2)Mg2(AsO4)3Iso. m3m (4/m 3 2/m) : Ia3d
20.8.18ManganberzeliiteNaCa2Mn2+2(AsO4)3Iso. m3m (4/m 3 2/m) : Ia3d
20.8.19Magnesiochlorophoenicite(Mg,Mn)3Zn2(AsO4)(OH,O)6Mon. 2/m : B2/m
20.8.20VillyaelleniteMnMn2Ca2(AsO4)2(HAsO4)2 · 4H2OMon. 2/m : B2/b
20.8.21Hematolite(Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23Trig. 3 : R3
20.8.22GrischuniteNaCa2Mn2+5Fe3+(AsO4)6 · 2H2OOrth.

Other InformationHide

Readily soluble in acids. Oxidizes readily upon exposure to air.
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 SynadelphiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Igelström (1884) Ak. Stockholm, Öfv.: 41: 86 (as Aimafibrit).
Sjögren (1884) Geologiska Föeningens I Stockholm Förhandlinger: 7: 220, 382.
Sjögren (1885) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 10: 126, 143.
Hamberg (1889) Geologiska Föeningens I Stockholm Förhandlinger: 11: 222.
Larsen, E.S. (1921) The Microscopic Determination of the Nonopaque Minerals, First edition, USGS Bulletin 679: 83 (as Hemafibrite).
Quensel and von Eckermann (1930) Geologiska Föeningens I Stockholm Förhandlinger: 52: 639 (as Allodelphite).
Machatschki (1931) Geologiska Föeningens I Stockholm Förhandlinger: 53: 187, 191.
Hurlbut (1937) American Mineralogist: 22: 526 (as Plumbosynadelphite).
Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged, 1124 pp.: 780-782, 919-920 (as Hemafibrite).
Moore, P.B. (1968) Contributions to Swedish mineralogy. I. Studies on the basic arsenates of manganese: retzian, hemafibrite, synadelphite, arsenoclasite, arseniopleite, and akrochordite. Arkiv. Mineral. Geol., 4(5), 425–444.
Moore, P. B. (1970): Crystal chemistry of the basic manganese arsenates: IV. mixed arsenic valences in the crystal structure of synadelphite. American Mineralogist 55, 2023-2037.

Internet Links for SynadelphiteHide

Localities for SynadelphiteHide

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.
  • Värmland
    • Filipstad
Nysten, P., Holtstam, D. and Jonsson, E. (1999) The Långban minerals. In Långban - The mines,their minerals, geology and explorers (D. Holtstam and J. Langhof, eds.), Swedish Museum of Natural History and Raster Förlag, Stockholm & Chr. Weise Verlag, Munich, pp. 89-183.
      • Nordmark Odal Field (Nordmarksberg)
Mineralogical Magazine(1978) 42, 133-136
Nysten, P. (1994): Alabandit och synadelfit, Nordmark. Långbansnytt. vol 10. [reprinted in: Långbansnytt. De första 20 åren 1983-2003. Långbansällskapet - Skrifter och rapporter. 2, 43]
Geologiska Föreningens i Stockholm Förhandlingar (1884): 7: 382; Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 782..
  • New Jersey
    • Sussex Co.
      • Franklin mining district
        • Ogdensburg
          • Sterling Hill
Moore, P.B. & Ito, J.: Am.Min.:63:938-940 (1978); Dunn(1995):Pt5:683.
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