Marble skarn - Antrim
Click the microscope button to view a thin section for this sample.
Click the microscope button to view a thin section for this sample.

Fact sheet

Marble skarn - Antrim

The sample of rare minerals comes from the boundary between a pure Cretaceous limestone with flint nodules and a Paleocene dolerite plug rising above the Antrim plateau lavas. Metamorphic and metasomatic changes induced by the intrusion led to recrystallisation close to the margin. The rock contains several unusual and rare minerals including larnite a mineral named after the town of Larne where the calcium orthosilicate was first recorded, and spurrite a calcium silicate mineral found exclusively in contact metamorphic boundaries between carbonate and basic magmas.

The thin section is dominated by large grains of spurrite which are clear in plain polarised light but exhibits strong second order colour between crossed polars. The left hand side of the thin section contains large areas of fine grained larnite, a fine grained colourless mineral, generally less than 100 microns in size in this rock, but which also exhibits strong second order birefringence colours.

54.908, -5.915
Scawt Hill, Country Antrim, Northern Ireland
About this collection

The United Kingdom Virtual Microscope (UKVM) collection consists of igneous, sedimentary and metamorphic rocks from around the UK.

It is intended as a teaching resource, helping to tell the story of the common rock types and how they form, and reflecting the history of the UK at the margins of the continent of Europe. The collection is a series of teaching sets, for example igneous rocks from the North Atlantic Igneous Province and SW England; high-temperature metamorphic rocks from Scotland and low-temperature metamorphic rocks from Wales; and sedimentary rocks, including English limestones and sandstones.

Sample details

Category guide  
Category Guide
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.
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.
Selecting one or more period, for example 'Jurassic'.
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.
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).
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: