History –Canadian Slate
The formation of slate begins at the bottom of primeval oceans, as the accumulation of fine clay mud. During the formation of mountain ranges, the pressure exerted compresses this clay layer to the hardness of stone. In Canada, conditions favourable to slate formation are found in several places in the Appalachian Mountains, from the Eastern Townships to Newfoundland.
Here are the major qualities of Canadian slate:
- The absolute impermeability of slate makes it resistant to freezing.
- Its layered structure enhances its flexibility and its resistance to impacts // better than ceramic tiles, in fact.
- Slate is inert to acids.
- Because it contains no pyrite and is free of internal oxides, slate resists delamination.
By contrast, because the internal structure of slate formed in warm seas contains large quantities of iron oxide, it is very porous and subject to constant delamination.