Porphyry is a volcanic rock which, though igneous like granite, has not been subjected to the same pressure and has cooled more slowly. Traditionally a cohabitant of gold ore bearing strata, it has a wide range of mineral inclusion and usually one of these (quartz, feldspar etc.) is of a coarser, larger nature than the other ingredients. It is usually stratified and often won by cleaving, as with sandstone.
Porphyry, in its rare purple form, was favoured by Roman emperors for the decoration of palaces and public buildings. Modern usage lies in the public realm for paving, setts, cobbles and small features. There is a range of warm tones, from red through to beige and yellow and the stone is resistant to large variations in temperature with good anti slip properties.
|Stone Type Code||Stone||Colour||Available Finishes|
|PGWR||Porphyry||Red||DS, T, F, P, RS, RA|
|PYRP||Porphyry||Purple||DS, T, F, P, RS, RA|
|PYBG||Porphyry||Green/Black||DS, T, F, P, RS, RA|
Paving, setts, small masonry blocks, plinths.
|DS||Diamond Sawn||F||Flamed||FP||Fine picked||RA||Riven, all faces|
|SB||Sandblasted||FF||Fair picked||RS||Riven and sawn edges||A||Axed|