Slate is a metamorphic rock, formed under great pressure from what was originally mudstone. Its origins in Wales date back to the Paleozoic age between 350 and 500 million years ago. Slate was originally used as a roofing material because it has two lines of breakability: cleavage and grain. This makes it possible to split slate into thin sheets, splitting the rock along its natural cleavage planes to produce thin plates which are then trimmed to shape and size.
There are three types of slate found in Wales - Silurian, Ordovician and Cambrian. Silurian is the youngest and least durable and is found in the Llangollen, Glyn Ceiriog and Corwen areas. Ordovician is found around Blaenau Ffestiniog and Corris, and is almost uniformly blue-grey. Cambrian is the oldest type and is found in the north around Snowdonia (Bethesda, Llanberis and the Nantlle Valley). The colour is variable with some veins being green and others plum, but the majority are blue/grey with a tendency towards purple.
Artistic Slate uses Cambian slate waste from quarries in the Snowdonia area to produce attractive, superior landscape material and also reconstitutes the slate into mouldable slate for table tops, roofing slates, plaques and collectable models.
