Porphyry

Porphyry is a textural term for an igneous rock consisting of large-grained crystals such as feldspar or quartz dispersed in a fine-grained silicate rich matrix or groundmass.
It is an extremely robust and hard-wearing stone that has a history of use dating back to Roman times, when it was used to construct the Roman Roadway, many of which are still in existence today, bearing testament to its strength and durability.