Portland stone formed in a marine environment, on the floor of a shallow, warm, sub-tropical sea probably near land (as evidenced by fossilised driftwood, which is not uncommon).

Small particles of sand or organic detritus, such as shell fragments, formed a nucleus, which became coated with layers of calcite as they were rolled around in the muddy micrite.

[3] The calcite gradually accumulated (by accretion) around the fragments of shell in concentric layers, forming small balls (of less than 0.5 mm diameter).

Over time, countless billions of these balls, known as "ooids" or "ooliths" (from the Greek for "egg-shaped" or "egg-stone"), became partially cemented together (or lithified) by more calcite, to form the oolitic limestone that is called Portland stone.

Geoff Townson conducted three years doctoral research on the Portlandian, being the first to describe the patch-reef facies and Dorset-wide sedimentation details.

To avoid disturbing the site at surface level, the company has applied and received permission to extract the stone using mining rather than quarrying techniques.

The reserves to the north will be quarried using the diamond bladed cutting machines, hydro bags and wire saws to shape the blocks.

This process avoids the use of dusty and noisy blasting as the primary extraction method, thereby protecting the surrounding environment, which has been designated as a Site of Special Scientific Interest (SSSI).

Open cast quarrying provides quicker extraction of raw block dimension stone whilst maintaining its integrity.

The coastal strip toward the southern tip of the island has permission to be worked by Portland Stone Firms and will provide in excess of 30 years of reserves.

This is done using "hydro-bags", which are thin, flat, steel bags or envelopes that when inflated with water under moderate pressure, are capable of producing the forces necessary to loosen the stone to the point where it can be easily removed using large wheeled loaders.

Splitting stone, using pneumatic drills is arduous work and so wire-saws have been introduced into the quarries, replacing much of the plug and feather cutting.

This method of extraction is significantly more expensive than blasting, but results in a higher yield thereby saving valuable reserves for future generations.

The East side of Buckingham Palace, the official London residence of King Charles III, including the balcony, was faced with Portland stone, first in 1854 and again in 1913.

Sir Christopher Wren used nearly one million cubic feet to rebuild St. Paul's Cathedral and many other minor churches after the Great Fire of London in 1666.

Portland stone is prevalent in Manchester despite the historical preferred use of hard-wearing materials, such as Burmantofts and sandstone to resist the harsh industrial environment.

[7] The Nottingham Council House, completed in 1929, is also built with Portland stone, as are the public buildings in Cardiff's civic centre.

Architect Charles Holden significantly used the stone in his major commissions of the 1920s and 1930s, including Senate House and 55 Broadway, the home of the London Underground.

The 1929 steel framed building (one of the first erected in the United Kingdom) of the London School of Hygiene & Tropical Medicine, based in Keppel Street, has a Portland stone façade to complete its stripped Classical design.

[8] After the Second World War (1939–1945), the bombed out centres of many English towns and cities, such as Plymouth, Bristol, Coventry and London were reconstructed using vast facades of Portland stone.

Oxford typically uses oolitic limestone in its buildings, and the Ashmolean Museum has been refurbished using a large amount of Portland stone.

[10] Following the First World War, Sir Edwin Lutyens used Portland stone (quarried from the bottom of Wakeham) to construct the Cenotaph in London's Whitehall.

Designed by Liam O'Connor Architects and Planning Consultants, it was completed in 2007 at a cost of over £6 million and bears the names of over 16,000 service personnel of the British Armed Forces killed since the Second World War.