When a diamond or another expensive stone is conflict-free, it was taken from the ground and sold without paying for guns, without hurting workers, and without feeding a war. The sad background is this: in some places, armed groups take the mines, harm the people there, and sell the stones to buy more weapons. People often call those stones blood diamonds, because people bled for them. Conflict-free is the opposite label — a way of saying this stone did not fund that violence. You will meet it in jewellery shops and in the news, most often on diamonds, though actually shops now put it on gold and other stones too. It is a serious, slightly formal word, not a word for a quiet day with no arguments. People do stretch it (a conflict-free workplace), but its real home is still the stone.