The buildings of the Sydney Central Business District (or CBD) are constructed from a wide range of geological materials (rock, aggregates, sand and cement) with most being locally sourced from New South Wales.
Many Sydney landmarks such as the Sydney Opera House and the Sydney Harbour Bridge contain locally sourced rock and aggregate.
All of the early or heritage buildings of Sydney were constructed from local materials. For stone, local Hawkesbury Sandstone was simply cut from outcrops either directly on-site or nearby. These early excavations are largely covered over by the CBD but some, such as the cuttings on Argyle street at the Rocks are still visible. In the early times of colonisation (1790 - 1840) excavation methods, transportation and access to building materials were very limited.
To extract lime for use as mortar, shellfish from Sydney Harbour and Botany Bay were crushed and roasted. The early bricks of Sydney were made from the local Ashfield Shale, giving them a distinctive reddish-brown colour. Good examples of this are the old wool mills at the Rocks and a more recent example (1920s) is the Palisades Hotel at the Rocks.
When it is first quarried, the Hawkesbury Sandstone is a pale grey colour. But within just a few weeks, siderite cement that holds the sand grains together reacts with the atmosphere and oxidises (rusts) to the iron hydroxide mineral goethite. This gives the Hawkesbury Sandstone a distinctive yellow colour which is why it is also known as yellow block. Major quarries for yellow block existed at Pyrmont, Maroubra, Five Dock, Bondi, Darling Harbour, Waverley, Paddington, and Woollahra. There were also many smaller quarries. The Pyrmont quarries were the most important, and there were 21 quarries operating at Pyrmont by 1854.
Because of its fine-grained nature and carbonate and clay rich cement, the sandstone reacts readily with the atmosphere and crumbles. This has been accelerated in the last 70 years by vehicle exhaust fumes and industrial pollution.
The Australian Museum is largely constructed of Hawkesbury Sandstone but has undergone many additions since it was first built in 1852.
The Mitchell Wing of the State Library of New South Wales dates from 1910 and is constructed of Hawkesbury Sandstone from former quarries at Pyrmont in Sydney.
Although most of St Mary's Cathedral is built from locally-derived yellow block, the recent spires are made from artificially-stained (to give the yellow colouration) Wondabyne Sandstone from the Gosford District on the central coast of New South Wales.
The Hawkesbury Sandstone was also widely used in early monument work such as in the carving of Queen Victoria on the Sydney Post Office building in Martin Place. Other major buildings featuring Hawkesbury Sandstone include St. Andrews Cathedral, Sydney Town Hall, Sydney University, Queen Victoria Building, the Lands Department Building, and the Art Gallery of New South Wales.
Various granites from the Bathurst District of New South Wales have been widely used in Sydney as dimension stone, monument stone, and aggregate.
The Anzac Memorial in Hyde Park is made of granite from the Sodwalls Quarry. Much of the construction of the Sydney Opera House is made of crushed granite from the Tarana Quarry.
A more recent building that utilises the granite as a facing and carving stone is the art deco design British Medical Association building in Macquarie Street.
Moruya, on the south coast of New South Wales is another source from which many construction materials of the buildings and monuments of Sydney were obtained. The rock used from Moruya is a granodiorite. Examples of its use include the Captain Cook Monument in Hyde Park. It was also used for the columns on the old Sydney Post Office building in Martin Place and for the Sydney Harbour Bridge pylons.
Because of architectural design, some buildings in the Sydney CBD are constructed from a number of different stones. A good example of this is the Commonwealth Bank building in Martin Place. Its lower floors are constructed from micro-syenite from Mount Gibraltar near Bowral in the Southern Highlands District of New South Wales but its upper floors are constructed from Hawkesbury Sandstone.
The Bowral micro-syenite has been used for many of the kerbstones lining Sydney's streets, because it is tough and hard-wearing. This stone has also been used for polished facings and columns on several major buildings, especially former bank buildings in the vicinity of Martin Place.
A wide range of ornamental marbles has been used for interior decoration of Sydney's buildings. These have striking patterns and attractive colours. Examples include those from Fernbrook, Bathurst district (staircase rails in Art Gallery of New South Wales), Caloola, Bathurst district (in vestibules of Prince Alfred Hospital, and Challis House in Martin Place), Borenore between Orange and Molong (panelling inside Central Railway Station, and staircase balusters in Art Gallery of New South Wales), Mudgee, Wombeyan (in GPO Building, and State Library new wing), Attunga near Tamworth, and Caleula near Orange (in St. James' Church).
Some of the construction materials in the Sydney CBD have been sourced from further afield. The dark facing stone on the fountain in Martin Place is made from black gabbro from the Black hills, Adelaide District, South Australia.
The recent paving stones around the Cook and Phillip Park aquatic and fitness centre are made from basaltic scoria from the Greater Melbourne District in Victoria
Many overseas materials are also used and include marble facing stones from various countries (such as those used in Thakral House, George Street) from various countries (such as those used on the floor of the Art Gallery of New South Wales) and ophicalcite facing stones from Italy (such as those used on the AMP Building at Circular Quay)
Copyright © Australian Museum, 2004