In Vermont, you can easily identify more than 10 different colors of slates. The most common is gray or
black, but there are some greens, blues, yellows, browns, purples, and reds. The colors of slate depend
on the types of elements and chemicals that are present during formation. For example, if iron were
present during formation the slate would be red (due to oxidation of the iron). Many slates exhibit
mottled or mixed colors.
The color of some slates fades over time due to exposure to the elements. Some
slates, called unfading, do not fade over time, making it a good roofing material (From A Project by
The most common and commercially important colors produced in the Vermont region are the following
according to the NSA (National Slate Association):
- also known as Sea Green, a green or
gray/green color when first
quarried; after application to the roof and exposure to the elements, a percentage of these slates weather.
SEMI-WEATHERING VERMONT GRAY
– a traditional slate-gray color ranging from
a clear appearance to having small black markings.
– a purple slate varying in shade. Some pieces are clear
while some pieces have green spots and marks.
UNFADING MOTTLED GREEN AND PURPLE
– green and purple combine to form unique
patterns in each slate.
– this slate exhibits shades ranging from a bright green
to gray/green tones that will not weather.
– a medium-texture slate, usually with black markings.
– a deep purple slate, at times almost burgundy in color,
which may have occasional green marks or inclusions.
– a medium gray slate with black stripes also known as Mottled
VERMONT BLACK AND SEMI-WEATHERING GRAY/BLACK
– slate with a medium to dark
gray color and darker linear markings to a medium-texture dark gray to black slate without lines.
- a bright red that will not change color, making it more
expensive to produce and contributing to its higher cost.