Headington stone is a limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 from the Headington Quarry

Headington Quarry

Headington Quarry is a residential district of Oxford, England, located east of Headington and west of Risinghurst, just inside the Oxford ring road in the east of the city. To the south is Wood Farm. Today the district is also known colloquially as "Quarry"...

 area of Oxford

Oxford

The city of Oxford is the county town of Oxfordshire, England. The city, made prominent by its medieval university, has a population of just under 165,000, with 153,900 living within the district boundary. It lies about 50 miles north-west of London. The rivers Cherwell and Thames run through...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

.

Geology

Around 160 million years ago, during the Late Jurassic

Late Jurassic

The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...

 period, Britain

Great Britain

Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 was located further south and was submerged beneath a subtropical sea. The warm conditions meant that coral reef

Coral reef

Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...

s could flourish. When the coral died, it was buried under successive layers of sediment and other debris. After millions of years, this became fossilized. It formed the Corallian Limestone

Corallian Limestone

Corallian Limestone is a coralliferous sedimentary rock, laid down in Jurassic times. It is a hard variety of "coral rag". Building stones from this geological structure tend to be irregular in shape. It is often found close to seams of Portland Limestone...

 that is now beneath the Headington Quarry area of Oxford.

Quarrying

Historically, there were a number of stone quarries in Headington Quarry. Headington stone was traditionally used for a number of the older Oxford University college buildings. In 1396, stone from quarrying in Headington was used to build the bell-tower for New College

New College, Oxford

New College is one of the constituent colleges of the University of Oxford in the United Kingdom.- Overview :The College's official name, College of St Mary, is the same as that of the older Oriel College; hence, it has been referred to as the "New College of St Mary", and is now almost always...

. It was also used for Oxford's city walls. Headington stone was used in the 1520s by Cardinal Wolsey to build his Cardinal College, now known as Christ Church

Christ Church, Oxford

Christ Church or house of Christ, and thus sometimes known as The House), is one of the largest constituent colleges of the University of Oxford in England...

.

Headington stone was particularly good for building since it can be cut in any direction and thus carved relatively easily. The stone was employed in buildings outside Oxford such as for Eton College

Eton College

Eton College, often referred to simply as Eton, is a British independent school for boys aged 13 to 18. It was founded in 1440 by King Henry VI as "The King's College of Our Lady of Eton besides Wyndsor"....

 and Windsor Castle

Windsor Castle

Windsor Castle is a medieval castle and royal residence in Windsor in the English county of Berkshire, notable for its long association with the British royal family and its architecture. The original castle was built after the Norman invasion by William the Conqueror. Since the time of Henry I it...

. Later stone extracted from the quarry was of less good quality, for example, that used to build the lower part of the Radcliffe Camera

Radcliffe Camera

The Radcliffe Camera is a building in Oxford, England, designed by James Gibbs in the English Palladian style and built in 1737–1749 to house the Radcliffe Science Library.-History:...

. The stone was prone to erosion by pollution.