أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
yes its ok
Are you referring to a stone like that of a pebble or a rock? If yes, I guess the answer is because they were created by nature to be colored black. If you are not referring to a gem stone then just disregard my post. :)
Hi Almira I'm afraid that I don't understand the question, it is either lateral thinking which I am incapable of, or I'm a bit slow, either way I apologise and would welcome the question phrased in a different way.