Time tested and made in the USA, the Vermont slate region produces some of the finest slate produced anywhere in the world. It is also the only deposit of “colored” stone that is currently quarried. Our colored stone include greens, greys, black, purples and red. There are also slates that are mottled with two or more colors—green and purple, grey and black for example. These colors and blends of colors are unique to Vermont slates.
In addition, we have chosen a select group of other slates to compliment our Vermont produced slates. These include the Penrhyn Unfading Purple from Wales, North Country Unfading Black from the Glendyne quarry in Quebec, and the Rathscheck Unfading Black from Spain. These three sources produce exceptionally good quality slate and are respected around the world. Learn more about them in our section on Roofing Slate Colors.
Slate, and slate-like stone, is produced in other parts of the world as well. There is a tremendous volume of black slate quarried in Spain. We have chosen to carry the Rathscheck Unfading Black as it is produced by a German company operating in Spain. Rathscheck is committed to producing the highest quality Spanish slate.
China has been exporting slate for a number of years. More recently we have seen Brazilian slate enter the US market, and even some material from India. To date we have chosen not to import or promote roofing slate from these slate regions for a variety of quality related reasons, including:
- Prevalence of oxidizable iron pyrite inclusions that can rust and discolor a roof or create holes in a slate
- High carbonate content which can cause the slates to turn white
- Exceptionally brittle or glassy stone that is difficult to cut
- High amounts of broken slates
- Inconsistent product
- High water absorption leading to delamination
- Debate about whether some material being marketed as slate is slate.