How was it formed?
Sediments containing clay and silt, laid down in horizontal beds, on the floor of an ancient river or sea formed Shale over a couple hundred million years. Tectonic pressures folded these beds into mountains. [Back to Top]
What is Slate composed of?
Shearing forces caused the Shale to mix with Calcite, Mica, Quartz, Pyrite, Volcanic Ash, and other minerals under enormous heat and pressure. The result was recrystallization into Slate deposits that can be as thick as half a mile. [Back to Top]
What gives Slate it's different colors?
The presence and concentration of trace elements such as Graphite and metallic oxides such as Iron and Titanium determine the color of the Slate. [Back to Top]
Is North American and European Slate the same?
It is theorized that all of the Earth's land masses were once joined together as a single continent known as "Pangaea" which, over 300 million years, split apart into the continents we now know. When one considers that the Slate deposits that run up the east coast of North America are virtually identical to those found in Wales it seems very possible. [Back to Top]
Pangaea The Continental Shift Theory
How old is Slate?
Slate is mind bogglingly ancient! 450-600 million years old. Slate is so ancient it pre-dates the existence of humans, dinosaurs, insects, and even complex plants. [Back to Top]
Are there fossils in Slate?
Very rarely the fossil of a simple water plant can be found. If you are lucky and discover a fossil in your slate, it's value to a collector can exceed what you paid for the sign! [Back to Top]