Paint coming off Gravel

Im just getting a tank ready for a few new fish that I am getting, and have some gravel that is different colours.
On advice I boiled this gravel before putting it in the tank, but have noticed that when I am rinsing it that the Paint/Coating is coming off the stones
I don't feel very comfortable putting this in the tank now as I would be worried about the welfare of the fish
Has anyone ever come across this before

cheap coloured gravel more hassle than its worth
i use B&Q Gravel its only £2 a bag needs a good wash like

i bought black gravel wen i first got my 6x2x2 cost me 22 quid a bag washed it placed it in tank and after 6 to 8 weeks noticed it was getting white bits in it,it was the unipac that i bought but it never did the fish any harm

i have had bits coming of my gravel before and it never done any harm to my fish either

Ok thanks guys, was a bit worried for a bit