Vote for your favorite mineral in #MinCup26! - Monazite-(Ce) vs. Andalusite
It's a showdown with rare earth elemental ore Monazite-(Ce) and index mineral Andalusite.
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

Chalcedony from
Kerguillo quarry, Guilers, Brest, Finistère, Brittany, France


Locality type:Quarry
Classification
Species:Quartz var: Chalcedony
Formula:SiO2
Confirmation
Validity:Believed Valid
Data
Mineral Data:Click here to view Chalcedony data
Locality Data:Click here to view Kerguillo quarry, Guilers, Brest, Finistère, Brittany, France
Data Identifiers
Mindat Occurrence Record ID:196414
Long-form Identifier:1:3:196414:1
GUID (UUID V4):0
Nearest other occurrences of Chalcedony
20.7km (12.9 miles) ⓘCléguériou, Logonna-Daoulas, Brest, Finistère, Brittany, France
44.4km (27.6 miles) ⓘBestrée, Pointe du Raz, Plogoff, Quimper, Finistère, Brittany, France
47.1km (29.2 miles) ⓘSiec island, Santec, Morlaix, Finistère, Brittany, France
48.9km (30.4 miles) ⓘCoat ar Roc'h area, Lannédern, Châteaulin, Finistère, Brittany, France
56.4km (35.1 miles) ⓘLe Ruguel, Collorec, Châteaulin, Finistère, Brittany, France
86.5km (53.8 miles) ⓘKernivaigne quarry, Riec-sur-Bélon, Quimper, Finistère, Brittany, France
98.9km (61.4 miles) ⓘLe Stang quarry, Guilligomarc'h, Quimper, Finistère, Brittany, France
References
Saget, P., J.P., Tissier (1989) Minéralogie descriptive de Kerguillo, près Brest [Descriptive mineralogy of Kerguillo, near Brest]. Le Cahier des Micromonteurs 25(3), 3-10
 
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 7, 2026 10:25:49
Go to top of page