Oamaru stone, sometimes called whitestone, is a hard, compact

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

, quarried at

Weston Weston may refer to: Places Australia * Weston, Australian Capital Territory, a suburb of Canberra * Weston, New South Wales * Weston Creek, a residential district of Canberra * Weston Park, Canberra, a park Canada * Weston, Nova Scotia * ...

, near

Oamaru Oamaru (; mi, Te Oha-a-Maru) is the largest town in North Otago, in the South Island of New Zealand, it is the main town in the Waitaki District. It is south of Timaru and north of Dunedin on the Pacific coast; State Highway 1 and the railway ...

Otago Otago (, ; mi, Ōtākou ) is a region of New Zealand located in the southern half of the South Island administered by the Otago Regional Council. It has an area of approximately , making it the country's second largest local government reg ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. Oamaru stone was used on many of the grand public buildings in the towns and cities of the southern

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

, especially after the financial boom caused by the

Central Otago goldrush The Otago Gold Rush (often called the Central Otago Gold Rush) was a gold rush that occurred during the 1860s in Central Otago, New Zealand. This was the country's biggest gold strike, and led to a rapid influx of foreign miners to the area – ...

of the 1860s. Initially used primarily in Oamaru itself, it became popular in Dunedin in around 1866, with the

University of Otago , image_name = University of Otago Registry Building2.jpg , image_size = , caption = University clock tower , motto = la, Sapere aude , mottoeng = Dare to be wise , established = 1869; 152 years ago , type = Public research collegiate u ...

's Registry Building being the first major structure in the city to make use of it.Limestones
, ''Transactions and Proceedings of the Royal Society of New Zealand'', vol 8 (1875), pp. 138–148. The city of

Dunedin Dunedin ( ; mi, Ōtepoti) is the second-largest city in the South Island of New Zealand (after Christchurch), and the principal city of the Otago region. Its name comes from , the Scottish Gaelic name for Edinburgh, the capital of Scotland. Th ...

and town of Oamaru both have many fine examples of Oamaru stone edifices, such as St Patrick's Basilica. The stone was used widely on buildings in many parts of New Zealand, including in the construction of both the Town Hall and the Chief Post Office in

Auckland Auckland (pronounced ) ( mi, Tāmaki Makaurau) is a large metropolitan city in the North Island of New Zealand. The List of New Zealand urban areas by population, most populous urban area in the country and the List of cities in Oceania by po ...

. The stone has been prominently used in combination with the more hard-wearing

bluestone Bluestone is a cultural or commercial name for a number of dimension or building stone varieties, including: * basalt in Victoria, Australia, and in New Zealand * dolerites in Tasmania, Australia; and in Britain (including Stonehenge) * felds ...

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

found in many parts of the southern South Island, creating a distinctive style of dark grey basalt walls with lighter Oamaru stone facings. Notable buildings to use this combination include the Dunedin Railway Station,

Otago University Registry Building The University of Otago Registry Building, also known as the Clocktower Building, is a Victorian and later structure in the city of Dunedin, New Zealand. It stands next to the banks of the Water of Leith and is constructed from contrasting dark ...

, Dunedin Law Courts, and

Christchurch Arts Centre The Arts Centre Te Matatiki Toi Ora is a hub for arts, culture, education, creativity and entrepreneurship in Christchurch, New Zealand. It is located in the Gothic Revival former Canterbury College (now the University of Canterbury), Christchur ...

. In Oamaru itself the stone is most commonly found as the primary construction material, with many of the town's more notable buildings (such as the

Waitaki District Council Waitaki District Council ( mi, Te Kaunihera ā-Rohe o Waitaki) is the territorial authority for the Waitaki District of New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two ...

building) showing its distinctive creamy colour. Its ease of working also appeals to sculptors and examples of Oamaru stone sculpture can be found throughout New Zealand.

Chemistry

The source of the stone is a 40-metre thick deposit inland from Oamaru consisting of bryozoan limestone. Oamaru stone is limestone with a uniform granular creamy white consistency and colour. Predominantly (90%) calcium carbonate, trace chemicals within it include alumina (1.5%),

iron oxide Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. All are black magnetic solids. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of whic ...

(0.5%) and

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...

(0.5%).Blair, G. W., (1877)
Oamaru Stone Export and Quarrying Co., New Zealand
, ''Robert Stout Collection'', vol. 87. Retrieved 29 January 2017. Its chemistry makes it similar to the Ketton stone

oolite Oolite or oölite (''egg stone'') is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Ancient Greek word for egg (ᾠόν). Strictly, oolites consist of ooids of diameter 0.25–2 ...

of southern England and France's

Caen stone Caen stone (french: Pierre de Caen) is a light creamy-yellow Jurassic limestone quarried in north-western France near the city of Caen. The limestone is a fine grained oolitic limestone formed in shallow water lagoons in the Bathonian Age about ...

, though it is considerably lighter in weight at 1.68 tonnes per cubic metre when freshly quarried, and 1.47 tonnes per cubic metre when completely dry.Limestones
, ''Transactions and Proceedings of the Royal Society of New Zealand'', vol 8 (1875), p144, converted from pounds per cubic foot. The stone is porous, making it susceptible to weathering in damp conditions, but sturdy in a moderate to dry climate. It is soft when first quarried, hardening on exposure to air. This, along with its uniform texture, makes it excellent for sculptural and ornamental purposes. The finished stonework has a creamy, sandy colour. It is not strongly resistant to pollution, and can be prone to surface crumbling, but is excellent as a material for internal architectural ornamentation. It is also greatly used for free-standing carvings and sculptures.

References

External links

Parkside Limestone Quarry, home of Oamaru Stone

Historic Oamaru Whitestone Civic Trust
{{commonscat, Oamaru stone, position=left Geology of New Zealand Limestone Building stone Oamaru Natural resources in Oceania

Chemistry

See also

References

External links