Properties of Slate | SpringerLink
Genuine colours of slate are black (a), red (b) and green (c); Superficial colours of slate are shown on a façade with slate from Gauteng, South Africa (d, e); f bright spots and areas in the purple slates (NY, USA); g natural and superficial spots on a slate (hand specimen); h Penrhyn slate on a roof in Saupsdorf (Saxony, Germany); i white ...