Welshite
A valid IMA mineral species
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About Welshite
Formula:
Ca4Mg9Sb3O4[Si6Be3AlFe2O36]
Colour:
Reddish black, reddish brown. brown-black; Brownish orange in transmitted light
Lustre:
Sub-Adamantine, Resinous
Hardness:
6
Specific Gravity:
3.77
Crystal System:
Triclinic
Member of:
Name:
Named in 1970 and formally described in 1978 by Paul (Paulus) Brian Moore in honor of Wilfred "Bill" Reinhardt Welsh [January 29, 1915 West Orange, New Jersey, USA - November 14, 2002 Newton, New Jersey, USA), public school science teacher, auxiliary police officer, motorcycle enthusiast, and amateur mineralogist of Upper Saddle River, New Jersey (USA). He was past President of the Franklin Mineral Museum and a significant benefactor to that institution, where his mineral and fossil collections now reside. Dr. Paul Moore was a student of Bill's and the naming acknowledged an extraordinary mentor whose verve inspired Paul to become a mineralogist.
Isostructural with:
Unique Identifiers
Mindat ID:
4267
Long-form identifier:
mindat:1:1:4267:9
GUID
(UUID V4):
(UUID V4):
35a87e5f-4571-46b5-8628-fe22c9643afc
IMA Classification of Welshite
Approved
IMA Formula:
Ca4[Mg9Sb5+3]O4[Si6Be3AlFe3+2O36]
Approval year:
1973
First published:
1978
Classification of Welshite
9.DH.40
9 : SILICATES (Germanates)
D : Inosilicates
H : Inosilicates with 4-periodic single chains, Si4O12
9 : SILICATES (Germanates)
D : Inosilicates
H : Inosilicates with 4-periodic single chains, Si4O12
69.2.1a.7
69 : INOSILICATES Chains with Side Branches or Loops
2 : Chains with Side Branches or Loops with P>2
69 : INOSILICATES Chains with Side Branches or Loops
2 : Chains with Side Branches or Loops with P>2
17.7.16
17 : Silicates Containing other Anions
7 : Silicates with vanadate, arsenate or antimonate
17 : Silicates Containing other Anions
7 : Silicates with vanadate, arsenate or antimonate
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Symbol | Source | Reference |
---|---|---|
Wel | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Welshite
Sub-Adamantine, Resinous
Transparency:
Transparent, Translucent
Colour:
Reddish black, reddish brown. brown-black; Brownish orange in transmitted light
Streak:
Pale brown
Hardness:
6 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
3.77 g/cm3 (Measured) 3.948 g/cm3 (Calculated)
Optical Data of Welshite
Type:
Biaxial (+)
RI values:
nα = 1.811 nγ = 1.831
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2V:
Measured: 45°
Birefringence:
0.020
Max Birefringence:
δ = 0.020
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r > v
Pleochroism:
Not Visible
Chemistry of Welshite
Mindat Formula:
Ca4Mg9Sb3O4[Si6Be3AlFe2O36]
Common Impurities:
Al,As,Mn,Be
Crystallography of Welshite
Crystal System:
Triclinic
Class (H-M):
1 - Pedial
Space Group:
P1
Setting:
P1
Cell Parameters:
a = 10.394(3) Å, b = 10.777(3) Å, c = 8.896(2) Å
α = 105.953°, β = 96.294°, γ = 124.948°
α = 105.953°, β = 96.294°, γ = 124.948°
Ratio:
a:b:c = 0.964 : 1 : 0.825
Unit Cell V:
738.8 Ă
Âł
Z:
1
Morphology:
Pseudomonoclinic. Crystals stout prismatic [001]. May be flattened on {010}. Free-standing crystals are rare.
Twinning:
Polysynthetic on {010}.
Crystal Structure
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2x2x2 | 3x3x3 | 4x4x4
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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) |
---|---|---|---|---|---|---|---|
0004268 | Welshite | Grew E S, Barbier J, Britten J, Halenius U, Shearer C K (2007) The crystal chemistry of welshite, a non-centrosymmetric (P1) aenigmatite- sapphirine-surinamite group mineral American Mineralogist 92 80-90 | 2007 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
7.32 Ă | (70) |
4.73 Ă | (60) |
2.910 Ă | (70) |
2.670 Ă | (60) |
2.530 Ă | (100) |
1.489 Ă | (70) |
1.460 Ă | (70) |
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
High-đ alteration and/or metamorphism | |
31 : Thermally altered carbonate, phosphate, and iron formations |
Type Occurrence of Welshite
Place of Conservation of Type Material:
U.S. National Museum of Natural History, Smithsonian Institution, Washington, D.C., USA
Geological Setting of Type Material:
Hematitic-dolomitic skarn
Associated Minerals at Type Locality:
Reference:
Moore, P.B. (1978) Welshite, Ca2Mg4Fe 3+Sb 5+O2[Si4Be2O18], A New Member of the Aenigmatite Group. Mineralogical Magazine: 42: 129-132.
Synonyms of Welshite
Other Language Names for Welshite
Relationship of Welshite to other Species
Member of:
Other Members of this group:
Dorrite | Ca4(Mg3Fe3+9)O4(Si3Al8Fe3+O36) | Tric. |
HĂžgtuvaite | Ca4[Fe2+6Fe3+6]O4[Si8Be2Al2O36] | Tric. 1 : P1 |
Leucorhönite | Ca2(Mg,Fe3+,Al)6(Si,Al)6O20 | Tric. |
Makarochkinite | (Ca,Na)4[Fe2+8Fe3+2Ti2]O4[Si8Be2Al2O36] | Tric. 1 : P1 |
Rhönite | Ca4[Mg8Fe3+2Ti2]O4[Si6Al6O36] | Tric. 1 : P1 |
Serendibite | Ca4[Mg6Al6]O4[Si6B3Al3O36] | Tric. 1 : P1 |
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
9.DH. | Gageite-2M | (Mn,Mg,Zn)42Si16O54(OH)40 |
9.DH. | Bavsiite | Ba2V2O2[Si4O12] |
9.DH. | Devilliersite | Ca4Ca2Fe3+10O4[(Fe3+10Si2)O36] |
9.DH. | Yuzuxiangite | Sr3Fe3+(Si2O6)2(OH) · 3H2O |
9.DH. | Louisfuchsite | Ca2(Mg4Ti2)(Al4Si2)O20 |
9.DH.05 | Leucophanite | NaCaBeSi2O6F |
9.DH.10 | Ohmilite | Sr3(Ti,Fe3+)(Si4O12)(O,OH) · 2-3H2O |
9.DH.15 | Haradaite | SrVSi2O7 |
9.DH.15 | Suzukiite | BaVSi2O7 |
9.DH.20 | Batisite | BaNaNaTi2(Si4O12)O2 |
9.DH.20 | Shcherbakovite | (K,Ba)KNa(Ti,Nb)2(Si4O12)O2 |
9.DH.20 | Noonkanbahite | BaKNaTi2(Si4O12)O2 |
9.DH.25 | Taikanite | Sr3BaMn2+2(Si4O12)O2 |
9.DH.30 | Krauskopfite | BaSi2O5 · 3H2O |
9.DH.35 | Balangeroite | (Mg,Fe2+,Fe3+,Mn2+)42Si16O54(OH)40 |
9.DH.35 | Gageite | Mn21(Si4O12)2O3(OH)20 |
9.DH.40 | Aenigmatite | Na4[Fe2+10Ti2]O4[Si12O36] |
9.DH.40 | Dorrite | Ca4(Mg3Fe3+9)O4(Si3Al8Fe3+O36) |
9.DH.40 | HĂžgtuvaite | Ca4[Fe2+6Fe3+6]O4[Si8Be2Al2O36] |
9.DH.40 | Krinovite | Na2Mg4Cr3+2(Si6O18)O2 |
9.DH.40 | Makarochkinite | (Ca,Na)4[Fe2+8Fe3+2Ti2]O4[Si8Be2Al2O36] |
9.DH.40 | Rhönite | Ca4[Mg8Fe3+2Ti2]O4[Si6Al6O36] |
9.DH.40 | Serendibite | Ca4[Mg6Al6]O4[Si6B3Al3O36] |
9.DH.40 | Wilkinsonite | Na2Fe2+4Fe3+2(Si6O18)O2 |
9.DH.40 | Leucorhönite | Ca2(Mg,Fe3+,Al)6(Si,Al)6O20 |
9.DH.40 | Kuratite | Ca2(Fe2+5Ti)O2[Si4Al2O18] |
9.DH.40 | Khesinite | Ca4(Mg3Fe3+9)O4(Fe3+9Si3)O36 |
9.DH.40 | UM1991-29-SiO:FeMgNa | Na4(Mg5Fe3+7)O4[Si9Fe3+3O36] |
9.DH.45 | Sapphirine | Mg4(Mg3Al9)O4[Si3Al9O36] |
9.DH.50 | Khmaralite | (Mg,Al,Fe)16[(Al,Si,Be)12O36]O4 |
9.DH.55 | Surinamite | (Mg,Fe)3Al4BeSi3O16 |
9.DH.55 | UM1988-26-SiO:AlMg | Mg4Al2O[Si3Al2O15] |
9.DH.60 | Deerite | (Fe,Mn)6(Fe,Al)3[Si6O17]O3(OH)5 |
9.DH.65 | Howieite | Na(Fe,Mn)10(Fe,Al)2Si12O31(OH)13 |
9.DH.65 | Taneyamalite | (Na,Ca)(Mn,Mg,Fe)12Si12(O,OH)44 |
9.DH.70 | Johninnesite | Na2Mn2+9Mg7(OH)8[AsO4]2[Si6O17]2 |
9.DH.75 | Agrellite | NaCa2Si4O10F |
Fluorescence of Welshite
Not fluorescent in UV
Other Information
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 Welshite
mindat.org URL:
https://www.mindat.org/min-4267.html
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References for Welshite
Reference List:
Localities for Welshite
Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - 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).
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 (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
Sweden (TL) | |
| Moore (1978) +1 other reference |
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LĂ„ngban Mine, LĂ„ngban Ore District, Filipstad, VĂ€rmland County, Sweden