Slate Rocks

Slate is a fine-grained homogeneous sedimentary rock composed of clay or volcanic ash which has been metamorphosed (foliated) so as to develop a high degree of fissility or slaty cleavage which is usually at a high angle to the planes of stratification. This high degree of fissility makes the better grades of slates an extremely useful roofing material (although its use has fallen in favor of synthetic and manufactured substitutes).

When choosing roofing materials, one must take into consideration the longevity of the roofing material, as well as the installation cost. Slate roofs have been known to last hundreds of years in comparison to the synthetic roof which typically lasts 10-20 years. Synthetic and manufactured roofing materials may initially save money at the time of installation, but the slate roof will last many lifetimes, making it the more permanent, economical choice.

Some of the finest slates in the world come from Portugal, Wales in the United Kingdom, Brazil and The Slate Valley of Vermont and New York.