Fine-grained, usually grey metamorphic rock that splits readily into thin slabs along its cleavage planes. It is the metamorphic equivalent of shale.
Slate is highly resistant to atmospheric conditions and can be used for writing on with chalk (actually gypsum). Quarrying slate takes such skill and time that it is now seldom used for roof and sill material except in restoring historic buildings.
Blue stands for the night sky and for water as a source of life. White represents peace. Red indicates the life-force. Green recalls nature and fertility. Effective date: 11 October 1991.