Porphyry is a volcanic stone of rare beauty. Each flagstone has two essential qualities; firstly a body colour ranging from a steel-grey to russet and even violet, and secondly a surface colour ranging from the unadorned body colour of the stone to a range of greens and brown mineral deposits. Sometime fern-like silhouettes mark the surface like primordial fossils. The stone provides understated charm, it looks rich and eyecatching with the wonderful property that it enhances and compliments most surroundings without stealing the scene. Porphyry splits flat with a slightly rough surface that offers excellent traction.  Porphyry is poor in the soluble minerals that plant life needs to survive with the result that it is difficult for anything to grow on the surface.  This makes porphyry particularly suitable for sites with a northern aspect.
The paving is calibrated to 30mm and therefore easier and quicker to lay.