Greenstone Vermont Slate colors are sourced from our 58 quarries, located in the heart of Vermont’s Slate Valley

The Slate Valley of Vermont is renowned for producing the world’s best quality slate. With only one exception — the unique Unfading Spanish Black — Greenstone Slate is manufactured into roofing slates in our Poultney, Vermont facilities. All Greenstone slate colors have been tested and meet the S1 ASTM engineering specification, (ASTM C406*), which means they exhibit all the physical characteristics of the best quality slate available.

Please note that slate color will vary somewhat because it is natural stone. The stone you receive will have its own unique natural color characteristics and in fact, your roof will be entirely unique — no other roof will be quite like it. The slate photographs on our website and in our literature are representative of the color categories of slate and a guide to what you can expect for your roof. Further, the way various devices/media represent the images you see will vary. Whether phone, tablet, desktop computer, TV or other device, none will display our photos in exactly the same way.

Get actual samples! Call us at 800 619 4333 to talk to us about getting actual slate samples for review. Please keep in mind however, that your slate delivery will still exhibit its own unique visual presentation!

Also available…

The available inventory of the below listed slate colors is dependent on the seasonal availability of that specific slate’s quarry. As with all Greenstone Slate, they also meet or exceed ASTM requirements as an S-1 rated roofing slate.

Vermont Clear Black (Semi-weathering)

This slate is an excellent hard-vein slate in shades of black. When weathered, 10-25% of slates will transform to chocolate and dark buff shades. The aesthetic result is a dark multi-toned roof with an abundance of character and surface texture.

Royal Purple (Semi-weathering)

Although this slate is a rich purple color, some pieces may have small markings of green. These durable Vermont slates are a favorite of architects and owners for custom homes where they are blended with other slates to create multi-colored roofs. Royal Purple slates are also popular on their own, as a roof covering for commercial, university and religious buildings. Royal Purple slates have historically exhibited a minimal amount of weathering.

Variegated Purple (Semi-weathering)

This slate has a predominately purple tone, with some having spots or streaks of green of varying size. In some slates, green maybe predominate with only tints of purple. Typically, in comparison to royal purple, a greater percentage of Variegated Purple slates will change upon exposure to shades of tan. As a result of its weathering characteristics, a vast array of colors can be expected. This makes variegated purple an excellent choice in color blends.

Non-weathering Red

This is a hard-vein red slate with excellent color, cleavage, and strength. This color becomes more pleasing with age. The dominant earthy red tone makes it an excellent choice as an accent color or for use in patterned slate roofs.

Important information about slate colors, weathering and fading

There are thousands of slate roofs still in service today installed in the 1800’s! With such a long history, many terms describing the material have been coined and over the years some have evolved into misinterpretation. For example, a common misconception associated with the nomenclature of describing slate occurs when the terms weathering and fading are erroneously interchanged. Below is a clarification of slate terms:

Nomenclature of Slate

Fading: The term “fading” refers to certain slates that after prolonged exposure to the elements exhibit a chalk-ashen residue on the exposed surface of the slate. The chalk-ashen residue is the result of a chemical reaction and the associated release of calcium from the body of the slate. This release weakens the structural integrity of slate and is detrimental to the slate’s life expectancy. The term is most often used in conjunction with the Blue Black or Black slates of Pennsylvania and Virginia.

Non-fading or Unfading: These terms refer to certain slates that after a prolonged exposure to the elements do not produce the chalk-ashen residue. “Non-fading” or “unfading” slates usually have greatly extended life expectancies over those slates prone to calcium release.

Classification of Colored Slate

Colored slate does not fade, but it will experience varying degrees of color change. This weathering of slate is due to the oxidation over time of minerals embedded in the slate. Depending on mineral content, the weathering process slowly changes the slate color. The color change is often a movement toward buff, brown, gray or tan. This surface oxidation is not detrimental to the slate’s structural integrity and does not shorten the life of a roof. Colored slates are classified in three types, based upon the degree of color change over time:

Weathering: The term “weathering” refers to slates that will exhibit the largest number of individual pieces that will transform from the original color to an earth tone.

Non-weathering: The term “non-weathering” refers to slates that exhibit the least amount of color change.

Semi-weathering: The term “semi-weathering” refers to roofing slates that have varying mineral content. Some of these slates will undergo a color change while others remain their original shade. The percentage of semi-weathering slates that will experience color change is variable depending upon the location in the quarry from which the slate was extracted.