Synadelphite
A valid IMA mineral species - grandfathered
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About Synadelphite
Formula:
Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O
Colour:
Colourless (crystal centers), red to brown (exteriors), blackish; colourless to pale brown or reddish in transmitted light.
Lustre:
Adamantine, Vitreous, Sub-Metallic
Hardness:
4½
Specific Gravity:
3.57 - 3.79
Crystal System:
Orthorhombic
Member of:
Name:
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.
Unique Identifiers
Mindat ID:
3852
Long-form identifier:
mindat:1:1:3852:8
IMA Classification of Synadelphite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Mn2+9(As3+O3)(As5+O4)2(OH)9·2H2O
Classification of Synadelphite
8.BE.50
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
43.5.12.1
43 : COMPOUND PHOSPHATES, ETC.
5 : Hydrated Compound Phosphates, etc·, Containing Hydroxyl or Halogen
43 : COMPOUND PHOSPHATES, ETC.
5 : Hydrated Compound Phosphates, etc·, Containing Hydroxyl or Halogen
20.8.8
20 : Arsenates (also arsenates with phosphate, but without other anions)
8 : Arsenates of Mn
20 : Arsenates (also arsenates with phosphate, but without other anions)
8 : Arsenates of Mn
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Syd | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Synadelphite
Adamantine, Vitreous, Sub-Metallic
Transparency:
Transparent, Translucent, Opaque
Comment:
Colourless material is vitreous, whereas the coloured material is adamantine to sub-metallic.
Colour:
Colourless (crystal centers), red to brown (exteriors), blackish; colourless to pale brown or reddish in transmitted light.
Hardness:
4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Imperfect/Fair
On {010}, imperfect.
On {010}, imperfect.
Fracture:
Irregular/Uneven, Conchoidal
Density:
3.57 - 3.79 g/cm3 (Measured) 3.56 g/cm3 (Calculated)
Comment:
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 Synadelphite
Type:
Biaxial (+)
RI values:
nα = 1.75 - 1.87 nβ = 1.751 - 1.88 nγ = 1.761 - 1.93
2V:
Measured: 37° to 40°, Calculated: 36° to 50°
Max. Birefringence:
δ = 0.011 - 0.060
Based on recorded range of RI values above.
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.
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:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
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.
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:
r > v
Pleochroism:
Visible
Comments:
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.
Y = Colourless or Brown
Z = light brown or Dark red-brown
Colours are for the colourless material and the coloured material, respectively.
Chemistry of Synadelphite
Mindat Formula:
Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O
Element Weights:
Elements listed:
Crystallography of Synadelphite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnma
Cell Parameters:
a = 10.754(11) Å, b = 18.865(17) Å, c = 9.884(14) Å
Ratio:
a:b:c = 0.57 : 1 : 0.524
Unit Cell V:
2,005.21 ų (Calculated from Unit Cell)
Z:
4
Morphology:
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).
Twinning:
Fourlings twinned by reflection on (100) and (010) of a "pseudo-orthogonal triclinic" lattice (crystal-structure determination however showed orthorhombic symmetry). Massive; reniform crusts.
Comment:
Originally thought to be triclinic-pseudo-orthorhombic.
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
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CIF File Best | x | y | z | a | b | c
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0000217 | Synadelphite | 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 |  | 1970 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.36 Å | (70) |
| 8.72 Å | (100) |
| 5.27 Å | (50) |
| 3.080 Å | (50) |
| 2.636 Å | (90) |
| 2.091 Å | (70) |
| 1.5996 Å | (70) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] | |
| 47e : [Vanadates, chromates, manganates] |
Type Occurrence of Synadelphite
Place of Conservation of Type Material:
Swedish Museum of Natural History, Stockholm, Sweden, number g28884.
Synonyms of Synadelphite
Other Language Names for Synadelphite
Varieties of Synadelphite
| Hemafibrite | A blood-red and fibrous variety of Synadelphite. |
| Plumbosynadelphite | A superfluous name for Pb-bearing synadelphite. |
Relationship of Synadelphite to other Species
Member of:
Other Members of Hematolite Group:
| Arakiite | (Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As5+O4)2(As3+O3)(OH)23 | Mon. m : Bb |
| Dixenite | CuMn2+14Fe2+(SiO4)2(As5+O4)(As3+O3)5(OH)6 | Trig. 3 : R3 |
| Hematolite | (Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23 | Trig. 3 : R3 |
| Kraisslite | Zn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16 | Orth. 222 : C2221 |
| Mcgovernite | Mn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21 | Trig. 3m : R3c |
| Turtmannite | (Mn,Mg)22.5Mg3-3x((V5+,As5+)O4)3(As3+O3)x(SiO4)3O5-5x(OH)20+x | Trig. |
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 8.BE.05 | Augelite | Al2(PO4)(OH)3 |
| 8.BE.10 | Grattarolaite | Fe3+3(PO4)O3 |
| 8.BE.15 | Cornetite | Cu3(PO4)(OH)3 |
| 8.BE.20 | Clinoclase | Cu3(AsO4)(OH)3 |
| 8.BE.25 | Gilmarite | Cu3(AsO4)(OH)3 |
| 8.BE.25 | Arhbarite | Cu2Mg(AsO4)(OH)3 |
| 8.BE.30 | Flinkite | Mn2+2Mn3+(AsO4)(OH)4 |
| 8.BE.30 | Argandite | Mn7(VO4)2(OH)8 |
| 8.BE.30 | Raadeite | Mg7(PO4)2(OH)8 |
| 8.BE.30 | Allactite | Mn2+7(AsO4)2(OH)8 |
| 8.BE.35 | 'Mineral E (of Dunn, et. al., 1982)' | |
| 8.BE.35 | Chlorophoenicite | (Mn,Mg)3Zn2(AsO4)(OH,O)6 |
| 8.BE.35 | Magnesiochlorophoenicite | (Mg,Mn)3Zn2(AsO4)(OH,O)6 |
| 8.BE.40 | Gerdtremmelite | (Zn,Fe)(Al,Fe)2(AsO4)(OH)5 |
| 8.BE.45 | Dixenite | CuMn2+14Fe2+(SiO4)2(As5+O4)(As3+O3)5(OH)6 |
| 8.BE.45 | Mcgovernite | Mn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21 |
| 8.BE.45 | Hematolite | (Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23 |
| 8.BE.45 | Turtmannite | (Mn,Mg)22.5Mg3-3x((V5+,As5+)O4)3(As3+O3)x(SiO4)3O5-5x(OH)20+x |
| 8.BE.45 | Carlfrancisite | Mn2+3(Mn2+,Mg,Fe3+,Al)42[As3+O3]2(As5+O4)4[(Si,As5+)O4]6[(As5+,Si)O4]2(OH)42 |
| 8.BE.45 | Arakiite | (Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As5+O4)2(As3+O3)(OH)23 |
| 8.BE.45 | Kraisslite | Zn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16 |
| 8.BE.55 | Holdenite | (Mn2+,Mg)6Zn3(AsO4)2(SiO4)(OH)8 |
| 8.BE.60 | Kolicite | Mn2+7Zn4(AsO4)2(SiO4)2(OH)8 |
| 8.BE.65 | Sabelliite | (Cu,Zn)2Zn(AsO4,SbO4)(OH)3 |
| 8.BE.70 | Jarosewichite | Mn2+3Mn3+(AsO4)(OH)6 |
| 8.BE.75 | Theisite | Cu5Zn5(AsO4,SbO4)2(OH)14 |
| 8.BE.80 | Coparsite | Cu4(AsO4,VO4)O2Cl |
| 8.BE.85 | Waterhouseite | Mn2+7(PO4)2(OH)8 |
| 8.BE.90 | Vasilseverginite | Cu9O4(AsO4)2(SO4)2 |
Other Information
Notes:
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.
Internet Links for Synadelphite
mindat.org URL:
https://www.mindat.org/min-3852.html
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Please feel free to link to this page.
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References for Synadelphite
Reference List:
Sjögren, Hj. (1884) Kristallografiska studier: VIII. Allaktit från Nordmarken. Geologiska Föreningen i Stockholm Förhandlingar, 7 (4) 220-236 doi:10.1080/11035898409443537
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin 679. US Geological Survey doi:10.3133/b679 p.83 - (as hemafibrite)
Quensel and von Eckermann (1930) Geologiska Föeningens I Stockholm Förhandlinger: 52: 639.(as Allodelphite)
Hurlbut, Cornelius S. (1937) On synadelphite and plumbosynadelphite. American Mineralogist, 22 (5) 526-533 (as Plumbosynadelphite)
Localities for Synadelphite
Showing 6 localities.
symbol to view information about a locality.
The Locality List
- 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).
All localities listed without proper references should be considered as questionable.
Sweden | |
| Holtstam et al. (1999) +1 other reference |
| Moore (1978) |
| Nysten (2003) | |
| [var: Hemafibrite] Geologiska Föreningens i Stockholm Förhandlingar (1884) +1 other reference | |
USA | |
| Moore et al. (1978) +1 other reference |
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Moss mine, Nordmark Odal Field, Filipstad, Värmland County, Sweden