n. 507 / March 2004

 

Introduction

 

Finland is rich in pre-Cambrian crystalline rocks that have been widely used over the centuries in various constructions. Their extraction and processing are currently an important economic sector. The country is a major supplier of red and brown "granites", at times with the typical orbicular texture (rapakivi granites). Materials with various colours and patterns expand the range of varieties available to architects. Oilstone (soapstone) is currently an important material for fireplaces and architectural applications.

 

Finnish natural stone materials

 

Quarrying activity began with the exploitation of erratics. "Granites" were used for centuries as a major material in many works. In particular, many churches were built with these materials in the Middle Ages. These rocks were not only quarried for use as building materials but were also studied scientifically: mention can be made, for example, of the famous work by geologist Sederholm. In some cases, it was the field work of geologists that laid the basis for the opening of new quarries. With the industrial revolution, the exploitation of "granite" became easier and more rational.

 

The oldest companies in the "natural stone" sector were AB Granit, founded in 1886, and Finska Stenindustri AB, which began operations in 1900 and worked rapakivi granite at Vehmaa since 1901 (Selonen & Paavo, 2003). In more recent times, major buildings have been installed all over the world (e.g. Turkmenistan).

 

Finland at the end of the 1800s also saw exploitation of oilstone, a steatite ("soapstone"), that became an important industrial sector in this period around Juuka. Currently, this area is witnessing a "rediscovery" of this historic material, so much so that quarrying and processing especially for ovens and fireplaces have become economically extremely important in the area.

 

Currently, Finnish natural stones (Table 1) are widely used on the domestic market in architecture and street furnishing but are also extensively exported to the rest of Europe, Asia and the United States. The most important quarries, with most of production, total about 40 sites; there are also minor quarries with seasonal activity. Processing is performed using modern, automated plant with numerical control machines. The fields of use are very wide-ranging and include floors and cladding, street furnishing, heating elements, "rotating spheres" on beds of water. The material is extensively used on both the domestic market and internationally.

 

Exploitation and processing are carried out with particular care for the environment, by restricting visual impact and recycling waste products. Quarrying activity is interrupted in Summer in view of higher levels of tourism. All waste material is re-used.

 

Currently, the main materials quarried are granite and soapstone (a term used to indicate a softer metamorphic rock, also known as steatite or oilstone).

 

Southern Finland produces rapakivi red granite (known commercially as Carmen Red, Karelia Red). The country also produces other red granites, as well as "granitic" rocks of various colours (brown, green, grey, yellow and black). In particular, rapakivi brown granite, also called Baltic Brown, is famous all over the world. The south west of the country also produces Balmoral red granite, without doubt another very famous natural stone from Finland.

 

Rapakivi granite is an anorogenic granite, dating back 1650-1540 million years. Other granites, older than rapakivi (2000-1830 million years), are worked in central Finland: they are more or less laminated metamorphic rocks.

 

The main red granites from Finland (Selonen & Harma, 2003) are: Balmoral Red, quarried at Vehmaa (fine-grain variety), Taivassalo and Uusikaupunki (large-grain variety), Porkkala Red, from Kirkonummi, Myrskyla Red, from the area of the same name, Carmen Red, worked at Virolahti, Karelia Red, produced in Anjalankoski. Other red granites include the so-called Eagle Red (Kotha), New Balmoral (Valkeala), Crystal Rose (Orivesi) amd the varieties Vitasaari Red, Rainbow and Lappia Salmon (Vitasaari).

 

We can also mention Vitasaari Pink (Vitasaari), while stones with a red-brown colour include Artic Red (Merijarvi) and Kuru Redbrown (Kuru). A red-green colour is offered by Moss Granite (Kalajoki). Esko Brown is worked at Taivassolo, while the famous Baltic Brown comes from Ylamaa. Exploitation of the latter variety began in the 1970s, and it soon became one of the most widely used granites all over the world. Monola Brown is worked at Lappeenranta, Fox Brown (or Magic Brown or Forest Pearl) at Oulainen. Baltic Green, a rapakivi green granite, comes from Ylamaa, Karelian Green from Kiuruvesi, Lappia Blue (or Blue Rose) from Kangasniemi. Grey granites include the famous Kuru Grey (Kuru and Tampere), a fine-grain granite, worked since the end of the 1800s and currently one of the main export granites. Another grey granitic rock is Artic White (Ristijarvi).

 

Although less well-known, Finnish rocks also include some varieties of yellow granite, such as the portphyry-granite Vitasaari Yellow (Vitasaari).

 

Black "granites" include the anortosite/anortositic gabbro Spectrolite (or Artic Blue or Finland Blue), from Ylama, which also produces gemstones, diorite Kuru Black or Kuru Black Star (Kuru), gabbro PM-Black (or Korpi Black or Korpilahti Black), quarried around Korpilahti and Muurame, diorite Blazing Black (Vitasaari), gabbro Oulainen Black (Oulainen), gabbro Saari Black (Saari), diabase PG-Black (Varpaisjarvi) - the blackest of all these stones.

 

Metamorphic rocks used as "granites" include Lilac Pearl (or Blue Star or Dark Green), garnet-bearing gneiss with cordierite, outcropping at Rautavaara, migmatitic gneiss Aurora (Mantsala), migmatite Lieto Red (Lieto), mica-schist with staurolite Platinum, a recently introduction from Tohmajarvi, gneiss with cordierite Amadeus

 

General "stones" in Finland include several varieties of schists, such as those commercialised as Orivesi Phyllite, Alajarvi Schist, Silver Flame, Viinijarvi Schist, Palijakka Gold, Lappia Silver.

 

Quartzites include Nilsia Quarztite and Lokka Quartzite.

 

A Finnish marble is Lappia Green, a dolomitic marble with green mica, but production is limited.

 

The second commercial category after granites, however, is steatite (soapstone), a metamorphic rock whose mineralogical composition includes talc, magnesite, chlorite and magnetite. This material is in great demand for the production of fireplaces, ovens and furnaces, exported throughout Europe and the United States. Currently, the rock is also used in architecture for interiors and exteriors. The main quarrying district is Juuka, in eastern Finland, where first began in 1893. Steatite is commercialised as Tulikivi Classic or Nunna Soapstone. Similar varieties are Kianta Blue (Suomussalmi) and Kivia Blue (Kuhmo), a very recent introduction. The Kyanta Sky variety is a talc-chlorite-schist with magnesite.

 

Tulikivi Green is a serpentinite, while Leopard Stone is a talc-schist with carbonate and serpentine.

 

By Laura Fiora