£144.95 per m². Prices stated below are per pallet containing 4m², this is our minimum order quantity and is exclusive of VAT and delivery charges. Trethowel Rustic is a traditional Cornish slate facing stone comes in a variety of sizes and finishes. It is popular with stonemasons due to the ease of working and the stunning results. It has a range of uses and can be used internally or externally depending on your project, whether it’s a time-honoured barn conversion, a contemporary new build or anything in between then this walling stone could be just what you’re looking for. It is a soft slate with rustic brown natural face coupled with undertones of light grey and soft yellow. It is metamorphic, around 400 million years old and splits very easily making it easy to work with.