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OK Graniitti · quarrying

Finnish granite, extracted as blocks for further processing.

Company

From black stone quarrying to a wider range

OK Graniitti's roots reach back to the late 1950s, when the company began quarrying black stone for memorials and building applications. Processing and contracting were added later.

Today, OK Graniitti supplies blocks and materials for landscaping and construction stonework. Quarrying aims to produce sound, accurately dimensioned blocks that yield as much usable stone as possible during processing.

Quarrying method

Diamond wire sawing in the quarry

We use diamond wire sawing to extract natural stone and reduce the need for blasting. A wire fitted with diamond beads cuts a controlled surface through the rock. The aim is to preserve the stone's integrity and produce blocks suitable for further processing.

Controlled cutting. Sawing helps define the block's shape and dimensions.
Careful use of material. Cutting directions follow the stone structure and processing requirements.
Quarry conditions. Suitability depends on factors including rock fractures, stress conditions and water availability.

Diamond wire sawing at an OK Graniitti quarry. Archive footage.

Oulainen Black, polished finish — Polished

Oulainen Black, bush-hammered finish — Bush-hammered

Surface samples: KIVI ry. Natural stone colour and structure vary; a sample does not represent every delivery batch.

Finnish natural stone

Oulainen Black, many expressions

Oulainen Black is a dark natural stone quarried at Ylipää in Merijärvi. Geologically it is gabbro, also referred to as black granite in the natural stone trade. KIVI ry's stone data sheet classifies it for indoor and outdoor use.

Surface finishing changes the stone's appearance. The polished sample is deeply dark, while the bush-hammered surface is lighter and evenly rough. Final colour and finish are confirmed with a project-specific sample.

Finlandia Hall's building history report documents Oulainen Black in the garden terrace retaining walls and stairs, and in the entrance courtyard paving. These surfaces are bush-hammered. The adjacent sample illustrates the finish; it is not a photograph of Finlandia Hall.

Sources: KIVI ry · Finlandia Hall building history report

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Arctic Red, bush-hammered finish — Bush-hammered

Surface samples: KIVI ry. Final colour and finish are confirmed with a project-specific sample.

Red-brown granite from Merijärvi

Arctic Red, warmth for public spaces

Arctic Red is a red-brown granite quarried at Ylipää in Merijärvi. Its medium- to coarse-grained mineral structure gives the surface a lively character. Suitable for indoor and outdoor use, its warm colour offers an alternative to grey and dark stone.

Polishing brings out the depth of colour and the mineral structure. Bush hammering and flaming create a rougher texture. For paving, stairs and solid stone products, the finish is specified to suit the use, appearance and surface requirements.

Arctic Red in completed projects

Senaatintori, Helsinki. Solid granite blocks define the square and also serve as seating.
Aleksanterinkatu, Helsinki. The street paving combines Arctic Red with Oulainen Black.
Narinkkatori, Kamppi. Arctic Red features in the square's planters and seating blocks.
Kauppakeskus Kaari, Helsinki. Arctic Red features in the shopping centre's stone surfaces.

Material data: KIVI ry · Project information: company project records

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