The Westminster Column, also known as the Crimea and Indian Mutiny Memorial, is a memorial commemorating 19 former pupils of Westminster School who died in two wars: ten in the Crimean War of 1854–56, and nine in the Indian Mutiny of 1857–58.
The memorial is installed on a plot outside the west entrance to Westminster Abbey, and north of the gatehouse leading to Dean's Yard.
At the top is a figure of St George slaying the dragon, with statues of Edward the Confessor, Henry III, Elizabeth I and Queen Victoria, and four lions flanking the base.
Earth Science Lesson:
The column itself is made of granite, and the base of Portland Stone.
One of the properties of granite is having large crystals that can be seen with the naked eye. Granite crystals will always be large enough to see easily. Therefore, if the crystals cannot be seen, the rock is not granite.
Granite is a common plutonic, intrusive, igneous rock. Plutonic means that it is magma that does not reach the surface of the earth and so cools very slowly underground. Intrusive means that it has moved into other rocks by force coming up from the Earth. Its colour ranges from brown to black, according to the proportions of its minerals.
Granite is crystalline in texture, and forms from the slow crystallisation of magma below the Earth’s surface. It is composed mainly of quartz and feldspar with smaller amounts of mica, amphiboles and other minerals:
Minerals: Mica - black; Potassium Feldspar - usually pink/red; Quartz - grey, white, glassy; Feldspar - white with a grey/yellow tinge; Amphibole - black/dark green
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Portland Stone is a form of limestone which formed slowly over the last 150 million years from tiny grains of sediment growing and then compacting. Portland Stone has been quarried on the Isle of Portland in Dorset since Roman times, and used as a building material since the 14th century.
It consists of calcium carbonate, and is formed by the compaction of calcite at the bottom of shallow lakes and seas. The presence of marine organisms and other fossils is often noticeable
The amount of cementation in Portland Stone is such that the stone is well formed to resist weathering, but not so well cemented that it can't be carved. Hence it is durable and can be used for columns, plinths, flooring etc. There are a number of different varieties of Portland Stone, with different appearances depending on the bed that it has been extracted from:
Basebed – the purest colour, contains small grey shell fragments
Whitbed – slightly more textured and with a bit more variation in colour. Typical Portland colour - creamy/white, although the large concentrations of grey shells can darken the overall colour.
Roach – the youngest Portland Stone (from the top layer) with the most colour variation and texture, often including impressions of shells and other marine creatures..
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In order to log the EarthCache you must answer the following questions:
1) Describe the overall colour and texture of the granite. Focusing on the crystals, what is their size and colour? What minerals do you think are present in the granite?
2) Look at the granite pillar closest to the road. The crystals on this section of stone are slightly smaller and more compact. Suggest why this might be.
3) From the above lesson, which form of Portland stone is the plinth made from?
On your log please include a photo of you or your GPS at GZ. Please do not show any area that will give answers away.
Please send your answers at the same time as you log the cache via message or email.