Portland stone is a limestone from the Tithonian stage of the Jurassic period quarried on the Isle of Portland, Dorset. The quarries consist of beds of white-grey limestone separated by chert beds. It has been used extensively as a building stone throughout the British Isles, notably in major public buildings in London such as St Paul's Cathedral and Buckingham Palace. It is also exported to many countries - Portland stone is used in the United Nations headquarters building in New York city, for example.
The term "Portland Cement" was coined by Joseph Aspdin who produced first in 1824 a hydraulic binder by burning a mixture of limestone and clay resembling the Roman cement and presenting a texture very close to that of the oolitic Portland stone. 1
All gravestones for British personnel killed in the First and Second World Wars are made out of Portland stone. However, these began to weather and detail such as the regimental badges were becoming difficult to view. The Commonwealth War Graves Commission began to use botticino, a white marble limestone, from about 1998. Portand stone was used for the £6 million memorial in Staffordshire, England, designed by Liam O'Connor Architects and Planning Consultants, that bears the names of over 16,000 service personnel who died since World War II2.
Three main "Portland Beds" are quarried. The Base and Portland Independent Top Whitbed beds are fine textured and contain few fossil remains, and so are popular for high quality work. The Portland Admiralty Roach bed is rougher with many fossils and its stone is notably used in the Cobb, at nearby Lyme Regis.
The Portland Sculpture and Quarry Trust was formed in 1983. The Trust is dedicated to preserving a knowledge and understanding of stone and the landscape from which it comes.
See also
- List of stone
- List of types of limestone
- Portland Admiralty Roach
- Portland Bowers Basebed
- Portland Bowers Lynham Whitbed
- Portland Bowers Saunders Whitbed
- Portland Grove Whitbed
- Portland Hard Blue
- Portland Independent Basebed
- Portland Independent Bottom Whitbed
- Portland Independent Top Whitbed
- Portland New Independent Whitbed
- Portland cement
References
- ^ Gerhartz, W. (Ed.) (1986). "Cement and concrete: see p. 492". In: Ullmann's Encyclopedia of Industrial Chemistry. Fifth completely revised edition, Volume A5. VCH Publisher, New York. ISBN 0-89573-155-X.
- ^ BBC NEWS | UK | Queen unveils new forces memorial
External links
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