单选题 Some of the earliest diamonds {{U}} {{U}}
1 {{/U}} {{/U}}from India. In the eighteenth {{U}} {{U}} 2
{{/U}} {{/U}}they were found in Brazil (巴西), and in 1866, large deposits
(矿石产地，矿床) were found {{U}} {{U}} 3 {{/U}} {{/U}}South Africa.
Now Africa {{U}} {{U}} 4 {{/U}} {{/U}}nearly all the world's
crude (未经加工的) stones which can become {{U}} {{U}} 5 {{/U}}
{{/U}}later. Until diamonds are {{U}} {{U}} 6 {{/U}} {{/U}}and
polished, they do not shine like those you see on a ring—they just {{U}}
{{U}} 7 {{/U}} {{/U}}like small, blue-grey stones.
Diamond itself is the only material {{U}} {{U}} 8 {{/U}}
{{/U}}enough to be cut and polished into diamonds—though recently, light beams
{{U}} {{U}} 9 {{/U}} {{/U}}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 {{U}} {{U}} 10
{{/U}} {{/U}}seven centuries.