Limestone - Purbeck Marble 2
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

Limestone - Purbeck Marble 2

This sample of building stone is Jurassic limestone from the Purbeck marble quarries near Swanage, Dorset. The building industry calls this type of rock marble and used it as a decorative stone in the construction of churches and cathedrals in southern England. In geology marble implies heating and high pressure but, although it does resemble true marble, this rock has not been metamorphosed.

In thin section the rock is composed of many whole and fragmented gastropod (Viviparus) shells. The shells form a rough alignment, which paralleled the original sea floor surface, and are supported in a fine-grained, calcite-rich mud matrix known as micrite. Some of the larger shells remained whole and were not completely filled by the mud, and in these cases the mud filled only the lower part of the shell, allowing geologists to identify which way was up in the rock. The spaces were later filled by large, clear calcite crystals, known as sparry calcite, which formed from later penetrating fluid

Watson 1911 Building Stones; MO 1316

Additional images
  • limestone - width 3.7 cm
  • limestone - width 13 cm
50.5982, -1.971
Purbeck marble quarries, near Swanage, Dorset
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

Rock-forming mineral
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: