Help mindat.org|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on MindatThe Mindat Store
Minerals by PropertiesMinerals by ChemistryRandom MineralSearch by minIDLocalities Near MeSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportAdd Glossary Item
StatisticsMember ListBooks & MagazinesMineral Shows & EventsThe Mindat DirectoryHow to Link to MindatDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Welshite

This page is currently not sponsored. Click here to sponsor this page.
Wilfred R. Welsh
Formula:
Ca4Mg9Sb3O4[Si6Be3AlFe2O36]
System:
Triclinic
Colour:
Reddish black, reddish ...
Hardness:
6
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:
Aenigmatite Group.

The only non-centrosymmetric member of the sapphirine group.

Classification of Welshite

Approved 1973
9.DH.40

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
17.7.16

17 : Silicates Containing other Anions
7 : Silicates with vanadate, arsenate or antimonate
mindat.org URL:
http://www.mindat.org/min-4267.html
Please feel free to link to this page.

Type Occurrence of Welshite

Place of Conservation of Type Material:
U.S. National Museum of Natural History, Smithsonian Institution, Washington, D.C., USA
Year of Discovery:
1973
Geological Setting of Type Material:
Hematitic-dolomitic skarn

Physical Properties of Welshite

Sub-Adamantine, Resinous
Diaphaneity (Transparency):
Transparent, Translucent
Colour:
Reddish black, reddish brown. brown-black; Brownish orange in transmitted light
Streak:
Pale brown
Hardness (Mohs):
6
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
3.77 g/cm3 (Measured)    3.71 g/cm3 (Calculated)

Crystallography of Welshite

Crystal System:
Triclinic
Class (H-M):
1 - Pedial
Space Group:
P1
Space Group 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°
Ratio:
a:b:c = 0.964 : 1 : 0.825
Unit Cell Volume:
V 738.8 ų
Z:
1
Morphology:
Pseudomonoclinic. Crystals stout prismatic [001]. May be flattened on {010}. Free-standing crystals are rare.
Twinning:
Polysynthetic on {010}.
X-Ray Powder Diffraction Data:
d-spacingIntensity
7.32 (70)
4.73 (60)
2.910 (70)
2.670 (60)
2.530 (100)
1.489 (70)
1.460 (70)

Optical Data of Welshite

Type:
Biaxial (+)
RI values:
nα = 1.811 nγ = 1.831
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.
Surface Relief:
Moderate
Dispersion:
r > v
Pleochroism:
Not Visible

Chemical Properties of Welshite

Formula:
Ca4Mg9Sb3O4[Si6Be3AlFe2O36]
All elements listed in formula:
Common Impurities:
Al,As,Mn,Be

Relationship of Welshite to other Species

Other Members of Group:
DorriteCa4(Mg3Fe93+)O4(Si3Al8Fe3+O36)
Høgtuvaite(Ca,Na)2(Fe2+,Fe3+,Ti)6[O2|Be(Si,Al)5O18]
LeucorhöniteCa2(Mg,Fe3+,Al)6(Si,Al)6O20
Makarochkinite(Ca,Na)2Fe42+Fe3+Ti[O2|BeAlSi4O18]
RhöniteCa2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
Serendibite(Ca,Na)2(Mg,Fe2+)3(Al,Fe3+)3[O2|(Si,Al,B)6O18]
9.DH.05LeucophaniteNaCaBeSi2O6F
9.DH.10OhmiliteSr3(Ti,Fe3+)(Si4O12)(O,OH) · 2-3H2O
9.DH.15HaradaiteSrVSi2O7
9.DH.15SuzukiiteBaVSi2O7
9.DH.20BatisiteBaNaNaTi2(Si4O12)O2
9.DH.20Shcherbakovite(K,Ba)KNa(Ti,Nb)2(Si4O12)O2
9.DH.25TaikaniteSr3BaMn22+(Si4O12)O2
9.DH.30KrauskopfiteBaSi2O5 · 3H2O
9.DH.35Balangeroite(Mg,Fe2+,Fe3+,Mn2+)42Si16O54(OH)40
9.DH.35GageiteMn21(Si4O12)2O3(OH)20
9.DH.40AenigmatiteNa2Fe52+Ti(Si6O18)O2
9.DH.40DorriteCa4(Mg3Fe93+)O4(Si3Al8Fe3+O36)
9.DH.40Høgtuvaite(Ca,Na)2(Fe2+,Fe3+,Ti)6[O2|Be(Si,Al)5O18]
9.DH.40KrinoviteNa2Mg4Cr23+(Si6O18)O2
9.DH.40Makarochkinite(Ca,Na)2Fe42+Fe3+Ti[O2|BeAlSi4O18]
9.DH.40RhöniteCa2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
9.DH.40Serendibite(Ca,Na)2(Mg,Fe2+)3(Al,Fe3+)3[O2|(Si,Al,B)6O18]
9.DH.40WilkinsoniteNa2Fe42+Fe23+(Si6O18)O2
9.DH.45Sapphirine(Mg,Fe)4-xAl4+x[Al4+xSi2-xO18]O2
9.DH.50Khmaralite(Mg,Al,Fe)16[(Al,Si,Be)12O36]O4
9.DH.55Surinamite(Mg,Fe)3Al4BeSi3O16
9.DH.60Deerite(Fe,Mn)6(Fe,Al)3[Si6O17]O3(OH)5
9.DH.65HowieiteNa(Fe,Mn)10(Fe,Al)2Si12O31(OH)13
9.DH.65Taneyamalite(Na,Ca)(Mn,Mg,Fe)12Si12(O,OH)44
9.DH.70JohninnesiteNa2Mn92+Mg7(OH)8[AsO4]2[Si6O17]2
9.DH.75AgrelliteNaCa2Si4O10F
17.7.1SuzukiiteBaVSi2O7
17.7.2FranciscaniteMn62+(V5+,☐)2(SiO4)2(O,OH)6
17.7.3Kurumsakite(Zn,Ni,Cu)8Al8V25+Si5O35 · 27H2O (?)
17.7.4Ardennite-(As)Mn42+Al4(AlMg)(AsO4)(SiO4)2(Si3O10)(OH)6
17.7.5Medaite(Mn,Ca)6(V,As)Si5O18OH
17.7.6JohninnesiteNa2Mn92+Mg7(OH)8[AsO4]2[Si6O17]2
17.7.7TiragalloiteMn42+(HAsSi3O13)
17.7.8DixeniteCuMn142+Fe2+(SiO4)2(As5+O4)(As3+O3)5(OH)6
17.7.9AsbecasiteCa3(Ti,Sn4+)Be2(AsO3)6(SiO4)2
17.7.10McgoverniteMn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21
17.7.11KraissliteZn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16
17.7.12Schallerite(Mn,Fe)16Si12As3O36(OH)17
17.7.13Nelenite(Mn,Fe)16(Si12O30)(OH)14[As33+O6(OH)3]
17.7.14KoliciteMn72+Zn4(AsO4)2(SiO4)2(OH)8
17.7.15YeatmaniteZn6Mn92+Sb25+(SiO4)4O12
17.7.17Katoptrite(Mn2+,Mg)13(Al,Fe3+)4Sb25+(SiO4)2O20
17.7.18ParweliteMn10Sb2As2Si2O24
17.7.19Långbanite(Mn2+,Ca)4(Mn3+,Fe3+)9Sb5+(SiO4)2O16
17.7.20ChapmaniteFe23+Sb3+(Si2O5)O3(OH)
17.7.21Cervandonite-(Ce)(Ce,Nd,La)(Fe3+,Fe2+,Ti,Al)3O2(Si2O7)(As3+O3)(OH)

Other Names for Welshite

Name in Other Languages:
German:Welshit
Spanish:Welshita

Other Information

Not fluorescent in UV
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 Welshite

Reference List:
Moore, Paul B. (1970) Mineralogy and Chemistry of Langban-type Deposits in Bergslagen, Sweden, Mineralogical Record, 1: 154-172.
Moore, P. B. (1978) Welshite, Ca2Mg4Fe 3+Sb 5+O2[Si4Be2O18], A New Member of the Aenignatite Group. Mineralogical Magazine: 42: 129-132.
American Mineralogist (1979): 64: 244 (abstract).
Canadian Mneralogist (1994): 32: 439.
Grew, E.S., et al.(2007): "The crystal chemistry of welshite, a non-centrosymmetric (P1) aenigmatite-sapphirine-surinamite group mineral": American Mineralogist, 92, 80-90.

Internet Links for Welshite

Specimens:
The following Welshite specimens are currently listed for sale on minfind.com.

Localities for Welshite

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 for a valid mineral species. (FRL) indicates first recorded locality for everything else. ? 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.
Sweden (TL)
 
  • Värmland
    • Filipstad
Min.Mag.(1978) 42, 129-132; 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.
Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2015, except where stated. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: August 5, 2015 11:36:52 Page generated: August 1, 2015 16:24:09