Besides one being made from clay and one from concrete there are a number of differences between the two.
As clay is a natural material, the colour is inherent within it; consequently, exposure to Ultra Violet light will not have an effect on the vibrancy of the colour over time.
Concrete however, is a pigmented material and over time and exposure to UV light there will be a reduction in the intensity of colour, this will not be a noticeable change due to the length of time it will take.
For further information please contact the Technical Advisory team on 0333 305 7901.