Slate geography · Explore the source
Roofing slates of the world.
Natural roofing slate has a geography as rich as its colors. Explore the world reference map, discover American slate regions and learn what the International Roofing Slate Classification describes.
Explore the U.S. map
American slate, region by region.
12 regional references. Interactive markers. Northeast detail. A downloadable map.
Open USA slate locations →
Slate Boss atlas · Global slate regions
The world roofing slate map
Explore our illustrated atlas of selected roofing slate regions, with a Europe detail inset and a numbered regional directory. Location references draw on Prof. Víctor Cárdenes’ January 2026 world map; the geographic base uses public-domain Natural Earth country boundaries.
Slate, Tile & Metal Guild of America
Education, craftsmanship and industry connections.
Visit slatetilemetalguild.org →The linked online source explains an earlier edition of Cárdenes’ reference map.
Where roofing slate is found
Selected regions included in the world atlas. This is a geographic reading guide, not a current supplier directory or a claim that every location is actively producing roofing slate.
United States
Vermont, New York, Pennsylvania and Virginia; additional historic districts and outcrops
Canada
Quebec and Newfoundland
Brazil
Minas Gerais
Argentina
San Luis
Spain
Lugo, La Cabrera, Valdeorras, Courel, Val d’Aran and Bernardos
Portugal
Valongo and Arouca
United Kingdom & Ireland
Wales, the Lake District, Scotland and Valentia
France
Angers, Fumay and other historic districts
Belgium & Luxembourg
Vielsalm, Bertrix and Haut-Martelange
Germany
Thuringia, Eifel, Hunsrück and other districts
Italy
Liguria and Valmalenco
Czechia & Slovakia
Moravian-Silesian slate districts and Marianka
Norway & Sweden
Alta, Oppdal, Otta and additional Scandinavian localities
China
Beijing, Hubei, Shaanxi and Jiangxi
India & Nepal
Himalayan regions, Rajasthan and Nepalese localities
Vietnam & Japan
Lai Chau and Ogatsu
South Africa
Gauteng
Australia
Willunga
Understand the stone
International Roofing Slate Classification
The IRSC groups roofing stone by rock type and color. Four rock families and three color families produce 12 main lithotypes. A code such as B1 describes black-gray slate; G2 describes green phyllite. It is a geological description—not an ASTM S1 durability rating, product certification or guarantee of roof life.
| Rock family | Black-gray | Green | Purple-red |
|---|---|---|---|
| Metalutite · 0 | B0 | G0 | R0 |
| Slate · 1 | B1 | G1 | R1 |
| Phyllite · 2 | B2 | G2 | R2 |
| Mica-schist · 3 | B3 | G3 | R3 |
The reference also identifies special roofing stones (ST) and variegated slate (R1a). The clean table above follows the four-family code pattern; the supplied sheet appears to repeat G2/R2 in its schist row.
Read the original reference sheet
The accompanying photograph explains rock formation, color and classification. Keep geological identification separate from roof specification: select roofing slate using applicable product tests, exposure conditions and a qualified designer’s requirements.
Download classification photoFurther reading & attribution
