Wood that has fallen will sometimes have interesting colouration caused by fungii known as spalting. This can be simple colours such as yellows, pinks and purples, or the more classic black lines which is a mineral deposit. The dried wood is quite harmless to humans. The spalting adds a level of interest to the visual bowl, and each piece will be as unique as a fingerprint! This bowl hasn't got the strong black lines, but the differing colours of spalting provide a nice contrast.
Currently being exhibited in a local craft shop.
YouTube: spaltedbeech4 video