Vote for your favorite mineral in #MinCup26! - Bournonite vs. Vesuvianite
Cogwheels of bournonite are up against colourful vesuvianite.
Log InRegister
Quick Links : The Mindat ManualThe Rock H. Currier Digital LibraryMindat Newsletter [Free Download]
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic TimeExplore Fossils
Minerals by PropertiesMinerals by ChemistryMineral Visual ExplorerAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral QuizTime Machine
Photo SearchPhoto GalleriesSearch by ColorPhoto Colour ExplorerNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography

Friar's Coat trial, Brithdir and Llanfachreth, Gwynedd, Wales, UKi
Regional Level Types
Friar's Coat trialTrial (Abandoned)
Brithdir and LlanfachrethCommunity
GwyneddCounty
WalesCountry
UKCountry

This page is currently not sponsored. Click here to sponsor this page.
PhotosMapsSearch
Latitude & Longitude (WGS84):
52° 46' 9'' North , 3° 42' 49'' West
Latitude & Longitude (decimal):
52.76937,-3.71365
GeoHash:
G#: gcmk5qrgc
GRN:
N36W02
UK National Grid Reference:
SH844205
Type:
Trial (Abandoned) - last checked 2020
Köppen climate type:
Cfb : Temperate oceanic climate
Nearest Settlements:
PlacePopulationDistance
Dolgellau2,688 (2017)12.0km
Upper Corris200 (2010)15.4km
Bala1,974 (2017)17.6km
Trawsfynydd628 (2017)20.4km
Machynlleth2,235 (2017)21.9km
Mindat Locality ID:
4284
Long-form identifier:
mindat:1:2:4284:3
GUID (UUID V4):
0
Other/historical names associated with this locality:
Tyllau mwn


A remote location marked on old OS maps as Tyllau mwn (mine shafts). Thought to be the site of an unsuccessful trial referred to under the name of Friar's Coat in 1770. According to the Geological Survey, iron ore (bedded oolitic ironstone with magnetite) was raised here in about 1878, 1910 and 1920.

Select Mineral List Type

Standard Detailed Gallery Strunz Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.


Mineral List


8 valid minerals.

Detailed Mineral List:

ⓘ Calcite
Formula: CaCO3
ⓘ Chamosite
Formula: (Fe2+,Mg,Al,Fe3+)6(Si,Al)4O10(OH,O)8
ⓘ Fluorapatite
Formula: Ca5(PO4)3F
ⓘ Ilmenite
Formula: Fe2+TiO3
ⓘ Magnetite
Formula: Fe2+Fe3+2O4
ⓘ Pyrrhotite
Formula: Fe1-xS
ⓘ Quartz
Formula: SiO2
ⓘ Stilpnomelane
Formula: (K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 2 - Sulphides and Sulfosalts
ⓘPyrrhotite2.CC.10Fe1-xS
Group 4 - Oxides and Hydroxides
ⓘMagnetite4.BB.05Fe2+Fe3+2O4
ⓘIlmenite4.CB.05Fe2+TiO3
ⓘQuartz4.DA.05SiO2
Group 5 - Nitrates and Carbonates
ⓘCalcite5.AB.05CaCO3
Group 8 - Phosphates, Arsenates and Vanadates
ⓘFluorapatite8.BN.05Ca5(PO4)3F
Group 9 - Silicates
ⓘChamosite9.EC.55(Fe2+,Mg,Al,Fe3+)6(Si,Al)4O10(OH,O)8
ⓘStilpnomelane9.EG.40(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O

List of minerals for each chemical element

HHydrogen
Hⓘ Chamosite(Fe2+,Mg,Al,Fe3+)6(Si,Al)4O10(OH,O)8
Hⓘ Stilpnomelane(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
CCarbon
Cⓘ CalciteCaCO3
OOxygen
Oⓘ CalciteCaCO3
Oⓘ Chamosite(Fe2+,Mg,Al,Fe3+)6(Si,Al)4O10(OH,O)8
Oⓘ FluorapatiteCa5(PO4)3F
Oⓘ IlmeniteFe2+TiO3
Oⓘ MagnetiteFe2+Fe23+O4
Oⓘ QuartzSiO2
Oⓘ Stilpnomelane(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
FFluorine
Fⓘ FluorapatiteCa5(PO4)3F
NaSodium
Naⓘ Stilpnomelane(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
MgMagnesium
Mgⓘ Chamosite(Fe2+,Mg,Al,Fe3+)6(Si,Al)4O10(OH,O)8
Mgⓘ Stilpnomelane(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
AlAluminium
Alⓘ Chamosite(Fe2+,Mg,Al,Fe3+)6(Si,Al)4O10(OH,O)8
Alⓘ Stilpnomelane(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
SiSilicon
Siⓘ Chamosite(Fe2+,Mg,Al,Fe3+)6(Si,Al)4O10(OH,O)8
Siⓘ QuartzSiO2
Siⓘ Stilpnomelane(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
PPhosphorus
Pⓘ FluorapatiteCa5(PO4)3F
SSulfur
Sⓘ PyrrhotiteFe1-xS
KPotassium
Kⓘ Stilpnomelane(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
CaCalcium
Caⓘ CalciteCaCO3
Caⓘ FluorapatiteCa5(PO4)3F
Caⓘ Stilpnomelane(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
TiTitanium
Tiⓘ IlmeniteFe2+TiO3
FeIron
Feⓘ Chamosite(Fe2+,Mg,Al,Fe3+)6(Si,Al)4O10(OH,O)8
Feⓘ IlmeniteFe2+TiO3
Feⓘ MagnetiteFe2+Fe23+O4
Feⓘ PyrrhotiteFe1-xS
Feⓘ Stilpnomelane(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O

Other Regions, Features and Areas containing this locality

British and Irish IslesGroup of Islands
Eurasian PlateTectonic Plate
EuropeContinent
UK

This page 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. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.
Quick NavTopCommoditiesMineral ListOther Regions
 
and/or  
Mindat.org® is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Mindat® and mindat.org® are registered trademarks of the Hudson Institute of Mineralogy.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2026, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph and Ida Chau.
Content on this site may not be used to train, fine-tune, or otherwise develop artificial intelligence or machine learning models without prior written permission - see our Terms & Conditions.
To cite: Ralph, J., Von Bargen, D., Martynov, P., Zhang, J., Que, X., Prabhu, A., Morrison, S. M., Li, W., Chen, W., & Ma, X. (2025). Mindat.org: The open access mineralogy database to accelerate data-intensive geoscience research. American Mineralogist, 110(6), 833–844. doi:10.2138/am-2024-9486.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: September 4, 2026 09:51:45 Page updated: August 2, 2025 14:36:46
Go to top of page