👉 Impennate is a type of rock in the Devonian period, which is one of the main geological periods in Britain. This type of rock is composed primarily of silicate minerals such as calcite and pyroxene, and it can be found on the surface or buried underground. The name "impennate" comes from the Irish word "impin", meaning "stone". It is recognized for its distinctive appearance with a rough texture and a high degree of transparency due to the presence of