We get different coloured flint in Britain. For example, in the Vale of Aylesbury you can pick up pieces of orange and brown flints from ploughed fields. In Poland they have chocolate brown flint – and it seems to have been sought out for the novelty, occurring in a narrow seam in what is known as the Holy Cross Mountains – see http://archaeologynewsnetwork.blogspot.co.uk/2013/06/7000-year-old-flint…
It begins, 'chocolate flint mining site …' which sounds very yummy, if a bit on the crunchy side. It seems this flint vein was being mined in Poland in the 5th and 4th millenniums BC.