Mindat Logo

Welshite

This page is currently not sponsored. Click here to sponsor this page.



Formula:
Ca
 
4
Mg
 
9
Sb
 
3
O
 
4
[Si
 
6
Be
 
3
AlFe
 
2
O
 
36
]
System:TriclinicColour:Reddish black, reddish ...
Hardness:6
Member of:Rhönite Group > Sapphirine Supergroup
Name:
Named after Wilfred R. Welsh (1915-2006), science teacher, auxillary 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 collection now reside. This species was named in his honor by one of his former students: Dr. Paul Moore.


Aenigmatite Group.

The only non-centrosymmetric member of the sapphirine group.

Classification of Welshite

IMA status:Approved 1973
Strunz 8th edition ID:8/F.14-70
Nickel-Strunz 10th (pending) edition ID:9.DH.40

9 : SILICATES (Germanates)
D : Inosilicates
H : Inosilicates with 4-periodic single chains, Si4O12
Dana 8th edition ID:69.2.1a.7

69 : INOSILICATES Chains with Side Branches or Loops
2 : Chains with Side Branches or Loops with P>2
Hey's CIM Ref.: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

Type Locality:Långban, Filipstad, Värmland, Sweden
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
Associated Minerals at type locality:
SwedenborgiteRoméite GroupRichteritePhlogopiteHausmannite
BerzeliiteAdelite

Physical Properties of Welshite

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

Crystallography of Welshite

Crystal System:Triclinic
Class (H-M):1 - Pedial
Space Group: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}.
Twinning:Polysynthetic on {010}.

Optical Data of Welshite

Type:Biaxial (+)
RI values: nα = 1.810 nβ = 1.830
2V:Measured: 45°
Maximum Birefringence:δ = 1.810

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

Chemical Properties of Welshite

Formula:
Ca
 
4
Mg
 
9
Sb
 
3
O
 
4
[Si
 
6
Be
 
3
AlFe
 
2
O
 
36
]
Simplified for copy/paste:Ca4Mg9Sb3O4[Si6Be3AlFe2O36]
Essential elements:Al, Be, Ca, Fe, Mg, O, Sb, Si
All elements listed in formula:Al, Be, Ca, Fe, Mg, O, Sb, Si
Common Impurities:Al,As,Mn,Be

Relationship of Welshite to other Species

Member of:Rhönite Group > Sapphirine Supergroup
Other Members of Group:

- +
Dorrite
Ca
 
4
(Mg
 
3
Fe
3+
9
)O
 
4
(Si
 
3
Al
 
8
Fe
3+
 
O
 
36
)
Høgtuvaite
(Ca,Na)
 
2
(Fe
2+
 
,Fe
3+
 
,Ti)
 
6
[O
 
2
|Be(Si,Al)
 
5
O
 
18
]
Leucorhönite
Ca
 
2
(Mg,Fe
3+
 
,Al)
 
6
(Si,Al)
 
6
O
 
20
Makarochkinite
Ca
 
2
Fe
2+
4
Fe
3+
 
Ti[O
 
2
|BeAlSi
 
4
O
 
18
]
Rhönite
Ca
 
2
(Mg,Fe
2+
 
,Fe
3+
 
,Ti)
 
6
[O
 
2
|(Si,Al)
 
6
O
 
18
]
Serendibite
(Ca,Na)
 
2
(Mg,Fe
2+
 
)
 
3
(Al,Fe
3+
 
)
 
3
[O
 
2
|(Si,Al,B)
 
6
O
 
18
]
Related Minerals - Nickel-Strunz Grouping):

- +
9.DH.05Leucophanite
NaCaBeSi
 
2
O
 
6
F
9.DH.10Ohmilite
Sr
 
3
(Ti,Fe
3+
 
)(Si
 
4
O
 
12
)(O,OH) · 2-3H
 
2
O
9.DH.15Haradaite
SrVSi
 
2
O
 
7
9.DH.15Suzukiite
BaVSi
 
2
O
 
7
9.DH.20Batisite
BaNaNaTi
 
2
(Si
 
4
O
 
12
)O
 
2
9.DH.20Shcherbakovite
(K,Ba)KNa(Ti,Nb)
 
2
(Si
 
4
O
 
12
)O
 
2
9.DH.25Taikanite
Sr
 
3
BaMn
2+
2
(Si
 
4
O
 
12
)O
 
2
9.DH.30Krauskopfite
BaSi
 
2
O
 
5
· 3H
 
2
O
9.DH.35Balangeroite
(Mg,Fe
2+
 
,Fe
3+
 
,Mn
2+
 
)
 
42
Si
 
16
O
 
54
(OH)
 
40
9.DH.35Gageite
Mn
 
21
(Si
 
4
O
 
12
)
 
2
O
 
3
(OH)
 
20
9.DH.40Aenigmatite
Na
 
2
Fe
2+
5
Ti(Si
 
6
O
 
18
)O
 
2
9.DH.40Dorrite
Ca
 
4
(Mg
 
3
Fe
3+
9
)O
 
4
(Si
 
3
Al
 
8
Fe
3+
 
O
 
36
)
9.DH.40Høgtuvaite
(Ca,Na)
 
2
(Fe
2+
 
,Fe
3+
 
,Ti)
 
6
[O
 
2
|Be(Si,Al)
 
5
O
 
18
]
9.DH.40Krinovite
Na
 
2
Mg
 
4
Cr
3+
2
(Si
 
6
O
 
18
)O
 
2
9.DH.40Makarochkinite
Ca
 
2
Fe
2+
4
Fe
3+
 
Ti[O
 
2
|BeAlSi
 
4
O
 
18
]
9.DH.40Rhönite
Ca
 
2
(Mg,Fe
2+
 
,Fe
3+
 
,Ti)
 
6
[O
 
2
|(Si,Al)
 
6
O
 
18
]
9.DH.40Serendibite
(Ca,Na)
 
2
(Mg,Fe
2+
 
)
 
3
(Al,Fe
3+
 
)
 
3
[O
 
2
|(Si,Al,B)
 
6
O
 
18
]
9.DH.40Wilkinsonite
Na
 
2
Fe
2+
4
Fe
3+
2
(Si
 
6
O
 
18
)O
 
2
9.DH.45Sapphirine
(Mg,Fe)
 
4-x
Al
 
4+x
[Al
 
4+x
Si
 
2-x
O
 
18
]O
 
2
9.DH.50Khmaralite
(Mg,Al,Fe)
 
16
[(Al,Si,Be)
 
12
O
 
36
]O
 
4
9.DH.55Surinamite
(Mg,Fe)
 
3
Al
 
4
BeSi
 
3
O
 
16
9.DH.60Deerite
(Fe,Mn)
 
6
(Fe,Al)
 
3
[Si
 
6
O
 
17
]O
 
3
(OH)
 
5
9.DH.65Howieite
Na(Fe,Mn)
 
10
(Fe,Al)
 
2
Si
 
12
O
 
31
(OH)
 
13
9.DH.65Taneyamalite
(Na,Ca)(Mn,Mg,Fe)
 
12
Si
 
12
(O,OH)
 
44
9.DH.70Johninnesite
Na
 
2
Mn
2+
9
Mg
 
7
(OH)
 
8
[AsO
 
4
]
 
2
[Si
 
6
O
 
17
]
 
2
9.DH.75Agrellite
NaCa
 
2
Si
 
4
O
 
10
F
Related Minerals - Hey's Index Grouping:

- +
17.7.1Suzukiite
BaVSi
 
2
O
 
7
17.7.2Franciscanite
Mn
2+
6
(V
5+
 
,☐)
 
2
(SiO
 
4
)
 
2
(O,OH)
 
6
17.7.3Kurumsakite
(Zn,Ni,Cu)
 
8
Al
 
8
V
5+
2
Si
 
5
O
 
35
· 27H
 
2
O (?)
17.7.4Ardennite-(As)
Mn
2+
4
(Al,Mg)
 
6
(Si
 
3
O
 
10
)(SiO
 
4
)
 
2
(AsO
 
4
,VO
 
4
)(OH)
 
6
17.7.5Medaite
(Mn,Ca)
 
6
(V,As)Si
 
5
O
 
18
OH
17.7.6Johninnesite
Na
 
2
Mn
2+
9
Mg
 
7
(OH)
 
8
[AsO
 
4
]
 
2
[Si
 
6
O
 
17
]
 
2
17.7.7Tiragalloite
Mn
2+
4
(HAsSi
 
3
O
 
13
)
17.7.8Dixenite
CuMn
2+
14
Fe
2+
 
(SiO
 
4
)
 
2
(As
5+
 
O
 
4
)(As
3+
 
O
 
3
)
 
5
(OH)
 
6
17.7.9Asbecasite
Ca
 
3
(Ti,Sn
4+
 
)Be
 
2
(AsO
 
3
)
 
6
(SiO
 
4
)
 
2
17.7.10Mcgovernite
Mn
 
19
Zn
 
3
(AsO
 
4
)
 
3
(AsO
 
3
)(SiO
 
4
)
 
3
(OH)
 
21
17.7.11Kraisslite
Zn
 
3
(Mn,Mg)
 
25
(Fe
3+
 
,Al)(As
3+
 
O
 
3
)
 
2
[(Si,As
5+
 
)O
 
4
]
 
10
(OH)
 
16
17.7.12Schallerite
(Mn,Fe)
 
16
Si
 
12
As
 
3
O
 
36
(OH)
 
17
17.7.13Nelenite
(Mn,Fe)
 
16
(Si
 
12
O
 
30
)(OH)
 
14
[As
3+
3
O
 
6
(OH)
 
3
]
17.7.14Kolicite
Mn
2+
7
Zn
 
4
(AsO
 
4
)
 
2
(SiO
 
4
)
 
2
(OH)
 
8
17.7.15Yeatmanite
Zn
 
6
Mn
2+
9
Sb
5+
2
(SiO
 
4
)
 
4
O
 
12
17.7.17Katoptrite
(Mn
2+
 
,Mg)
 
13
(Al,Fe
3+
 
)
 
4
Sb
5+
2
(SiO
 
4
)
 
2
O
 
20
17.7.18Parwelite
Mn
 
10
Sb
 
2
As
 
2
Si
 
2
O
 
24
17.7.19Långbanite
(Mn
2+
 
,Ca)
 
4
(Mn
3+
 
,Fe
3+
 
)
 
9
Sb
5+
 
(SiO
 
4
)
 
2
O
 
16
17.7.20Chapmanite
Fe
3+
2
Sb
3+
 
(SiO
 
4
)
 
2
(OH)
17.7.21Cervandonite-(Ce)
(Ce,Nd,La)(Fe
3+
 
,Fe
2+
 
,Ti,Al)
 
3
O
 
2
(Si
 
2
O
 
7
)(As
3+
 
O
 
3
)(OH)

Other Names for Welshite

Synonyms:
IMA1973-019
Other Languages:
German:Welshit
Spanish:Welshita

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 Welshite

Reference List:

- +
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": Am. Min. 92, 80-90.

Internet Links for Welshite

Search Engines:
  • Look for Welshite on Google
  • Look for Welshite images on Google
  • External Links:
  • Look for Welshite on Webmineral
  • Look for Welshite on Athena Mineralogy
  • Look for Welshite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Welshite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Buy from David K Joyce minerals
  • High-end worldwide specimens & outstanding customer service
  • Rare and Unusual minerals at Mineralogical Research Company
  • DAKOTA MATRIX offers Cabinet and Rare Species from Worldwide Localities.
  • Buy RARE Minerals from Rocks of Africa
  • Top quality minerals from Kristalle of California
  • Lapis Mineral Magazin
  • rare and unusual minerals mainly crystallized
  • Wilensky Fine Minerals
  • Buy from McDougall Minerals
  • Search for Welshite on Well-Arranged Molecules
  • Fine Minerals from Weinrich Minerals, Inc.
  • Jobs:
  • Mining & Geology Jobs
  • Localities for Welshite

    The 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. ? 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
     
    • 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  
    Search Google  
    Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
    Current server date and time: January 5, 2014 03:53:25
    Mineral and Locality Search
    Mineral:
    and/or Locality:
    Options
    Fade toolbar when not in focusFix toolbar to bottom of page
    Hide Social Media Links
    Slideshow frame delay seconds