单选题 Some of the earliest diamonds 1 from India. In the eighteenth 2 they were found in Brazil (巴西), and in 1866, large deposits (矿石产地，矿床) were found 3 South Africa. Now Africa 4 nearly all the world"s crude (未经加工的) stones which can become 5 later. Until diamonds are 6 and polished, they do not shine like those you see on a ring—they just 7 like small, blue-grey stones.
Diamond itself is the only material 8 enough to be cut and polished into diamonds—though recently, light beams 9 lasers have been developed which can bore (穿) holes in diamonds. A fully cut "shining" diamond has 58 faces (表面，平面). A place in Holland (荷兰) and a place in Belgium (比利时) have been the centres of the diamond cutting and polishing industry 10 seven centuries.