1. Definition

Like slate, lauze is a very fine-grained, very hard shale that is extracted in layers from local open-cast quarries. Stones of all sizes are cut. They are not "standardized", varying in thickness, length and appearance.

The appearance of lauzes varies in material and color, depending on the region and the vein from which it was extracted: silvery-gray, bluish, greenish or brown tones (depending on the iron content), dark tones (quartz and mica) or light tones (feldspar).

Lauze roofs are typical of mountainous regions. Highly weather-resistant and offering excellent insulating performance, shale roofing is heavy and expensive.

It's a roof made from flat stones such as phonolith (Massif Central) or Brando stone (Haute-Corse). A relatively hard volcanic, schistose or limestone rock, lauze is traditionally used as a...