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Gwynedd (Merionethshire), Wales, UK

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Following the reorganisation of 1996, the Unitary Authority of Gwynedd was reconstituted from the administrative county of Gwynedd minus the parts now within the Unitary Authorities of Conwy and Isle of Anglesey. As such, it covers most of the traditional counties of Merionethshire and Caernarfonshire.

The administrative county of Gwynedd was itself only formed during 1974 from the amalgamation of the traditional counties of Merionethshire, Caernarfonshire and Anglesey that that date back to the middle ages.

Mineral specimens from locations listed within this section (ie the part of the Unitary Authority of Gwynedd that previously formed the traditional county of Merionethshire may therefore be labeled as coming from Gwynedd or Merionethshire depending upon the time they were collected.

Mineral specimens from locations within the part of the Unitary Authority of Gwynedd that previously formed the traditional county of Caernarfonshire are listed seperately within that section.




Mineral list contains entries from the region specified including sub-localities


Mineral List:
  		•  Acanthite ?
    Ag
     
    2
    		S
    Description: The National Museum of Wales database "The Minerology of Wales" (http://www.nmgw.ac.uk/en/791/)has raised doubts regarding the identifications of acanthite and sylvanite at this location.
    Reference: [The National Museum of Wales database "The Minerology of Wales"]
  		•  Actinolite
    ☐Ca
     
    2
    		(Mg,Fe
    2+
     
    		)
     
    5
    		(Si
     
    8
    		O
     
    22
    		)(OH)
     
    2
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 925-935.]
  		•  Albite
    Na[AlSi
     
    3
    		O
     
    8
    		]
    Reference: [UKJMM 16:30-33]
  		•  Aleksite
    PbBi
     
    2
    		Te
     
    2
    		S
     
    2
    Reference: [BMS Database]
  		•  Allanite-(Ce)
    {CaCe}{Al
     
    2
    		Fe
    2+
     
    		}[O|OH|SiO
     
    4
    		|Si
     
    2
    		O
     
    7
    		]
    Reference: [No reference listed]
  		•  Altaite
    PbTe
    Reference: [BMS Database]
  		•  Anatase
    TiO
     
    2
    Reference: [UKJMM 16:30-33]
    Site Photo
    Moel Ysgyfarnogod, Eisingrug, Gwynedd (Merionethshire), Wales, UK
    © Peter Haas
  		•  Anglesite
    PbSO
     
    4
    Reference: [No reference listed]
  		•  Ankerite
    Ca(Fe
    2+
     
    		 ,Mg,Mn
    2+
     
    		)(CO
     
    3
    		)
     
    2
    Reference: []
  		•  'Apatite'
    Reference: [UKJMM 16:30-33]
  		•  Apatite-(CaF)
    Ca
     
    5
    		[F|(PO
     
    4
    		)
     
    3
    		]
    Reference: [Matthews and Scoon (1964)]
  		•  Aragonite
    CaCO
     
    3
    Reference: [BMS Database]
  		•  Arsenopyrite
    FeAsS - (Fe
     
    0.90
    		Co
     
    0.10
    		)AsS
    Reference: [BMS Database]
    Site Photo
    Castell Carn Dochan, Llanuwchilyn, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  		•  Bismuth
    Bi
    Reference: [BMS Database]
  		•  Bismuthinite
    Bi
     
    2
    		S
     
    3
    Reference: [BMS Database]
    Site Photo
    Castell Carn Dochan, Llanuwchilyn, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  		•  Bornite
    Cu
     
    5
    		FeS
     
    4
    Reference: [BMS Database]
  		•  Boulangerite
    Pb
     
    5
    		Sb
     
    4
    		S
     
    11
    Reference: [BMS Database]
  		•  Bournonite
    PbCuSbS
     
    3
    Reference: [BMS Database]
  		•  Brochantite
    Cu
     
    4
    		[(OH)
     
    6
    		|SO
     
    4
    		]
    Reference: [BMS Database]
  		•  Brookite
    TiO
     
    2
    Reference: [UKJMM 16:30-33]
  		•  Calcite
    CaCO
     
    3
    Reference: [Ian Jones collection]
    Site Photo
    Gwynfynydd Mine (Gwyn Mine; Morgan Mine; Mount Morgan Mine; British Gold Fields), Ganllwyd, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Ian Jones
  		•  Chalcoalumite
    CuAl
     
    4
    		[(OH)
     
    12
    		|SO
     
    4
    		] · 3H
     
    2
    		O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  		•  Chalcocite
    Cu
     
    2
    		S
    Reference: [BMS Database]
  		•  Chalcophyllite
    Cu
     
    18
    		Al
     
    2
    		[(OH)
     
    9
    		|SO
     
    4
    		|AsO
     
    4
    		]
     
    3
    		 · 33H
     
    2
    		O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  		•  Chalcopyrite
    CuFeS
     
    2
    Reference: [BMS Database]
  		•  Chamosite
    (Fe
    2+
     
    		,Mg)
     
    5
    		Al[(OH)
     
    8
    		|AlSi
     
    3
    		O
     
    10
    		]
    Reference: [Matthews and Scoon (1964)]
  		•  'Chlorite Group'
    Reference: [BMS Database]
  		•  Chrysocolla
    (Cu,Al)
     
    2
    		H
     
    2
    		Si
     
    2
    		O
     
    5
    		(OH)
     
    4
    		·nH
     
    2
    		O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  		•  Clinochlore
    (Mg,Fe
    2+
     
    		)
     
    5
    		Al[(OH)
     
    8
    		|AlSi
     
    3
    		O
     
    10
    		]
    Reference: [UKJMM 16:30-33]
  		•  Clinozoisite
    {Ca
     
    2
    		}{Al
     
    3
    		}[O|OH|SiO
     
    4
    		|Si
     
    2
    		O
     
    7
    		]
    Reference: [Gilbey, J.W., 1968. The mineralogy, paragenesis and structure of the ores of the Dolgellau Gold Belt, Merionethshire, and associated wall rock alteration. Unpublished Ph.D thesis, University of London, UK.]
  		•  Cobaltite
    CoAsS
    Reference: [BMS Database]
  		•  Copper
    Cu
    Reference: [recorded in the National Museum of Wales database]
  		•  Covellite
    CuS
    Reference: [BMS Database]
  		•  Cryptomelane
    K(Mn
    4+
     
    		,Mn
    2+
     
    		)
     
    8
    		O
     
    16
    Reference: [national museum of wales database]
    Site Photo
    Moel Llyfnant Mine, Moel Llyfnant, Llanycil, Gwynedd (Merionethshire), Wales, UK
    © ian jones
  		•  Cuprite
    Cu
     
    2
    		O
    Reference: [BMS Database]
  		•  Devilline
    CaCu
     
    4
    		(SO
     
    4
    		)
     
    2
    		(OH)
     
    6
    		·3H
     
    2
    		O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  		•  Dolomite
    CaMg(CO
     
    3
    		)
     
    2
    Reference: [National Museum of Wales datebase]
  		•  Epidote
    {Ca
     
    2
    		}{Al
     
    2
    		Fe
    3+
     
    		}[O|OH|SiO
     
    4
    		|Si
     
    2
    		O
     
    7
    		]
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 925-935.]
  		•  Erythrite
    Co
     
    3
    		(AsO
     
    4
    		)
     
    2
    		·8H
     
    2
    		O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  		•  Felsőbányaite
    Al
     
    4
    		[(OH)
     
    10
    		|SO
     
    4
    		] · 4H
     
    2
    		O
    Reference: [Ball, D.F., 1969. Basaluminite from Cambrian rocks near Harlech. Mineralogical Magazine, 37, 291-293.]
  		•  Galena
    PbS
    Reference: [ref: Goldmining in Western Merioneth, T. A. Morrison (undated)]
  		•  Gibbsite
    Al(OH)
     
    3
    Reference: [BMS Database]
  		•  Goethite
    α-Fe
    3+
     
    		O(OH)
    Reference: [No reference listed]
  		•  Gold
    Au
    Reference: [BMS Database]
    Site Photo
    Clogau St Davids Mine (Clogau Mine; St David's Mine), Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Ian Jones
  		•  Gold
    var: Electrum
    (Au, Ag)
    Reference: [Mineralogical Magazine 1884 6 : 108-108]
  		•  Gypsum
    Ca[SO
     
    4
    		] · 2H
     
    2
    		O
    Reference: [BMS Database]
    Site Photo
    Castell Carn Dochan, Llanuwchilyn, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  		•  Halotrichite
    FeAl
     
    2
    		(SO
     
    4
    		)
     
    4
    		·22H
     
    2
    		O
    Reference: [No reference listed]
  		•  Hedleyite
    Bi
     
    7
    		Te
     
    3
    Description: Hedleyite occurs as tiny inclusions in galena on a specimen (K3) in the Kingsbury Collection held at the Natural History Museum, London (Naden, 1988). This, the Uk's first occurrence, is the only known specimen from Clogau Mine. No other examples have come to light despite extensive studies (National Museum of Wales database). Whilst confirmed analytically, the occurrence should be treated with caution due Kingsbury's known creative specimen provenancing practices (Ryback et al., 1998).
    Reference: [BMS Database]
  		•  Hemimorphite
    Zn
     
    4
    		[(OH)
     
    2
    		|Si
     
    2
    		O
     
    7
    		] · H
     
    2
    		O
    Reference: [No reference listed]
  		•  Hessite
    Ag
     
    2
    		Te
    Reference: [BMS Database]
  		•  Hollandite
    Ba(Mn
    4+
     
    		,Mn
    2+
     
    		)
     
    8
    		O
     
    16
    Reference: [National Museum of Wales database ]
    Site Photo
    Mynydd Nodol Mine (Manganese Royal Mine), Mynydd Nodol, Llanycil, Gwynedd (Merionethshire), Wales, UK
    © ian jones
  		•  Hydrozincite
    Zn
     
    5
    		[(OH)
     
    3
    		|CO
     
    3
    		]
     
    2
    Reference: [No reference listed]
  		•  Ilmenite
    Fe
    2+
     
    		TiO
     
    3
    Reference: [Matthews and Scoon (1964)]
  		•  Langite
    Cu
     
    4
    		[(OH)
     
    6
    		|SO
     
    4
    		] · 2H
     
    2
    		O
    Reference: [BMS Database]
  		•  Lead ?
    Pb
    Description: Readwin reported native lead with gold from the Dolgellau Gold-belt. Neither occurrence has since been confirmed.
    Reference: [Natiom]
  		•  Lithiophorite
    (Al,Li)MnO
     
    2
    		(OH)
     
    2
    Reference: [national museum of wales database]
  		•  Mackinawite
    (Fe,Ni)
     
    9
    		S
     
    8
    Reference: [BMS Database]
  		•  Magnetite
    Fe
    2+
     
    		Fe
    3+
    2
    		O
     
    4
    Reference: [Matthews and Scoon (1964)]
  		•  Malachite
    Cu
     
    2
    		[(OH)
     
    2
    		|CO
     
    3
    		]
    Reference: [BMS Database]
  		•  Marcasite
    FeS
     
    2
    Reference: [No reference listed]
  		•  Matildite
    AgBiS
     
    2
    Reference: [BMS Database]
  		•  Melanterite
    FeSO
     
    4
    		·7H
     
    2
    		O
    Reference: [Bevins, R.E. & Mason, J.S., 1998. Welsh Metallophyte and metallogenic evaluation project: Results of a Minesite Survey of Gwynedd. National Museums of Wales, Cardiff.]
  		•  'Mica Group'
    Reference: [BMS Database]
  		•  Molybdenite
    MoS
     
    2
    Reference: [BMS Database]
  		•  Monohydrocalcite
    CaCO
     
    3
    		·H
     
    2
    		O
    Reference: [BMS Database]
  		•  Nagyágite
    Pb
     
    5
    		Au(Te,Sb)
     
    4
    		S
     
    5-8
    Reference: [BMS Database]
  		•  Orthoclase
    K[AlSi
     
    3
    		O
     
    8
    		]
    Reference: [No Reference]
  		•  Pentlandite
    (Fe,Ni)
     
    9
    		S
     
    8
    Reference: [BMS Database]
  		•  Phlogopite
    KMg
     
    3
    		[(OH,F)
     
    2
    		|AlSi
     
    3
    		O
     
    10
    		]
    Reference: [No Reference]
  		•  Pickeringite
    MgAl
     
    2
    		(SO
     
    4
    		)
     
    4
    		·22H
     
    2
    		O
    Reference: [No reference listed]
  		•  Pilsenite
    Bi
     
    4
    		Te
     
    3
    Reference: [BMS Database]
  		•  Pyrargyrite
    Ag
     
    3
    		SbS
     
    3
    Reference: [national Museum of Wales database]
  		•  Pyrite
    FeS
     
    2
    Reference: [ref: Goldmining in Western Merioneth, T. A. Morrison (undated)]
  		•  Pyrolusite
    MnO
     
    2
    Reference: [National Museum of Wales database]
  		•  Pyrrhotite
    Fe
     
    7
    		S
     
    8
    		, (-4M), also given as Fe
     
    1-x
    		S (x = 0 - 0.2)
    Reference: [BMS Database]
  		•  Quartz
    SiO
     
    2
    Reference: [ref: Goldmining in Western Merioneth, T. A. Morrison (undated)]
  		•  Rhodochrosite
    MnCO
     
    3
    Reference: [P.M. Allen, A.A. Jackson: Geological Excursions in the Harlech Dome, BGS, 1985]
  		•  Rhodonite
    MnSiO
     
    3
    Reference: [BMS Database]
  		•  Rutile
    TiO
     
    2
    Reference: [UKJMM 16:30-33]
  		•  Scorodite
    Fe
    3+
     
    		AsO
     
    4
    		·2H
     
    2
    		O
    Reference: [BMS Database]
  		•  'Sericite'
    Reference: [UKJMM 21:37]
  		•  Spessartine
    Mn
    2+
    3
    		Al
     
    2
    		[SiO
     
    4
    		]
     
    3
    Reference: [P.M. Allen, A.A. Jackson: Geological Excursions in the Harlech Dome, BGS, 1985]
  		•  Sphalerite
    (Zn,Fe
    2+
     
    		)S
    Reference: [ref: Goldmining in Western Merioneth, T. A. Morrison (undated)]
  		•  Stilpnomelane
    (K,Ca,Na)(Fe
    2+
     
    		,Mg,Al,Fe
    3+
     
    		)
     
    8
    		(Si,Al)
     
    12
    		(O,OH)
     
    36
    		 · nH
     
    2
    		O
    Reference: [Specimen in the Natural History Museum, London]; Mineralogical Magazine 1964 33 : 1032-1037]
  		•  Sylvanite ?
    (Au,Ag)
     
    2
    		Te
     
    4
    Description: The National Museum of Wales database "The Minerology of Wales" (http://www.nmgw.ac.uk/en/791/)has raised doubts regarding the identifications of acanthite and sylvanite at this location.
    Reference: [The National Museum of Wales database "The Minerology of Wales"]
  		•  Synchysite-(Ce)
    Ca(Ce,La)[F|(CO
     
    3
    		)
     
    2
    		]
    Reference: [UKJMM 16:30-33]
    Site Photo
    Manod Quarry (Manod New Setts Quarry), Blaenau Ffestiniog, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  		•  Tellurobismuthite
    Bi
     
    2
    		Te
     
    3
    Reference: [BMS Database]
  		•  Tetradymite
    Bi
     
    2
    		Te
     
    2
    		S
    Reference: [BMS Database]
  		•  Tetrahedrite
    (Cu,Fe,Ag,Zn)
     
    12
    		Sb
     
    4
    		S
     
    13
    Reference: [BMS Database]
  		•  Thaumasite
    Ca
     
    3
    		[CO
     
    3
    		|SO
     
    4
    		|Si(OH)
     
    6
    		] · 12H
     
    2
    		O
    Reference: [BMS Database]
  		•  Titanite
    CaTi[O|SiO
     
    4
    		]
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 925-935.]
  		•  Tyrolite
    Ca
     
    2
    		Cu
     
    9
    		[(OH)
     
    4
    		|(H
     
    2
    		O)
     
    11
    		|CO
     
    3
    		|(AsO
     
    4
    		)
     
    4
    		] · 0-1H
     
    2
    		O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  		•  'Wad'
    Reference: [P.M. Allen, A.A. Jackson: Geological Excursions in the Harlech Dome, BGS, 1985]
  		•  Wroewolfeite
    Cu
     
    4
    		[(OH)
     
    6
    		|SO
     
    4
    		] · 2H
     
    2
    		O
    Reference: [BMS Database]
  		•  Xenotime-(Y)
    YPO
     
    4
    Reference: []


    95 entries listed. 89 valid minerals.

    Localities in this Region:
    UK
     
    • Wales
      • Gwynedd (Merionethshire)
        • Cader Idris (Cadair Idris)
          • Arthog
          • Barmouth
          • Llanfachreth
          • Llanuwchilyn
        • Eisingrug
        • Harlech
        • Llandecwyn
          • Minffordd
          • Coed Llyn y Garnedd
          • Moel Llyfnant
          • Mynydd Nodol
          • Pantllwini

    The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database!
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    Copyright © Jolyon Ralph and Ida Chau 1993-2009. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the 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 hundreds of members and supporters. If you would like to add information to improve the quality of our database, then click here to register. Current server date and time: 26th Nov 2009 15:46:44