| Reference | N9 |
| NAME | Trevillett (riven) |
| TYPE | Slate |
| GEOLOGY | Devonian. Upper Devonian Slate Beds |
| COUNTY | Cornwall |
| COLOUR | Blue/grey/green. Pyrite grains common |
| TEXTURE | Fine grained. Pronounced irregular cleavage |
| BLOCK SIZE LXBXH (mm) | |
| SUITABILITY | Roofing and flooring |
| USES (1) | Buckstead Abbey, Abbey Farm |
| USES (2) | Tavistock Town Hall |
| USES (3) | |
| USES (4) | |
| Stone Names | Tredorn Phyllites |