TableĀ 5.

Mineralogical composition (values in per cent) of studied roofing slates based on a semi-quantitative XRD analysis

QuartzMuscoviteChloriteParagoniteChloritoidMicroclinePyrrhotite
Luarca slate42.133.812.17.42.51.70.4
MuscoviteQuartzAlbiteChloriteOrthoclaseAnatasePyrite
Culm slate39.623.516.616.23.80.2<0.1