Hard Blue Stone

Found in the Lower Purbeck beds this material was previously discarded for aggregate, as it was too hard to cut as dimensional stone. Fortunately the introduction of the latest extraction and manufacturing technology has meant Albion Stone are able to offer this unique material. To date it has been proving exceptionally popular as a flooring material, a contrast band to other Portland Stones and for vanity units and counter tops.

Blue Purbeck Marble
http://projects.bre.co.uk/ConDiv/stonelist/stonelist.html

PS: A ardósia é uma possibilidade mas realmente não pode se dizer que seja uma pedra dura (hard) pelo contrário, é até um tanto frágil (convivo com esse tipo de piso na minha casa ;))

De qualquer modo, mais uma opção

Boa sorte


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Note added at 4 hrs 57 mins (2003-08-01 19:40:43 GMT)
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Esqueci de dizer: Hard Blue Stone é um tipo de limestone (pedra calcária)