The type of land in which the fossil wood has been preserved determines its aesthetics. Its shades of colour indicate the presence of a clayey soil, if they tend to a warm or gravely shade, in the case of colder shades. The darker the colour, the older the wood, with an age that varies between several centuries and some thousands of years. Among the trees of origin we find the Oak more frequently, while Beech, Poplar, Ash and Elm trees are even more rare and precious. 