M12. Glaucophane Schist - Ile de Groix
Collection:
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Microscope
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Fact sheet

M12. Glaucophane Schist - Ile de Groix

Fold in glaucophane epidote schist from Ile de Groix, cut from a beach cobble.  The section is on the thick side because the blue-lilac amphibole glaucophane has rather low birefringence and tends not to show second order colours as seen here.

Rotation 1 contains glaucophane and garnet

Rotation 2 contains glaucophane and epidote

Rotation 3 contains glaucophane and mica (or chlorite?)

See: https://geosciences-test.univ-rennes1.fr/IMG/pdf/MB_PP-lawsonite-JMG.pdf

Age of metamorphism is 420-400 Ma

Map
47.643432, -3.482666
Description:
Ile de Groix, off the coast of Brittany, France
About this collection

A group of iCRAG members (UCC, TCD, NUIG and UCD) in partnership with The Open University have created a new collection of Irish rocks and associated learning materials for the Virtual Microscope of Earth Sciences.

The project which is entitled 'The Geoscience e-Laboratory (GeoLab): Developing Digital Teaching and Learning Resources for the Virtual Microscope' seeks to develop open access teaching resources in the form of interactive exercises and assessment rubrics for the Virtual Microscope. Find out more about the project at the GeoLab website.

The Collection was created using funding from the Faculty of Engineering, Mathematics and Science at Trinity College, Dublin, and the National Forum Teaching and Learning Enhancement Fund. One sample (Merensky Reef) showcasing x-ray element maps in addition to the usual PPL/XPL/REF images was funded by Prof. Balz Kamber's MetalIntelligence EU training network grant.

Sample details

Type
metamorphic
Rock-forming mineral
garnet
glaucophane
epidote
mica
Category guide  
Category Guide
Title
Refers to any word or phrase that appears in the individual rock names. Names are generally descriptive; they allow users to search for broad terms like ‘granite’ as well as more specific names such as ‘breccia’. However, the adjacent descriptions of the specimens captures a wider range of general words and phrases and is a more powerful search tool.
Description
Refers to any word or phrase that appears anywhere in the descriptions of the specimens
Accessory minerals
Minerals that occur in very low abundance in a rock. They are usually not visible with the naked eye and contribute perhapssver, they often dominate the rare elements such as platinum group metals.
Rock-forming minerals
Minerals that make up the bulk of all rock samples and are also the ones used in rock classi?cation.
Timescale
Selecting one or more period, for example 'Jurassic'.
Theme
A term used to group together related samples that are not already gathered into a single Collection. For instance, there is a ‘SW England granites’ theme that includes such rock types as granite, hydrothermal breccia, skarn and vein samples.
Category
A general term used to label a rock sample. It is a useful way of grouping similar samples throughout a collection. Category names are often, but not exclusively, common rock names (e.g. granite, basalt, dolerite, gabbro, greisen, skarn, gneiss, amphibolite, limestone, sandstone).
Owner
The owner of the sample that appears in the collection. For example, NASA owns all the samples that appear in the Moon Rocks collection
We would like to thank the following for the use of this sample: