世界金刚石的产量在逐年增长(表1)。但1971年例外,这是由于扎伊尔、南非和纳米比亚产量下降,世界产量由3800万克拉降至3600万克拉。扎伊尔产量下降是由于工业金刚石在世界市场上找不到销路。南非和纳米比亚的产量下降则是因为对大粒金刚石(大于1克拉)需求增长,小粒金刚石相应减产的结果。例如, World diamond production is increasing year by year (Table 1). However, except in 1971, this was due to a decline in output in Zaire, South Africa and Namibia, and a decrease in world output from 38 million carats to 36 million carats. The decline in output in Zaire is due to the fact that industrial diamond can not find a way out in the world market. The decline in production in South Africa and Namibia is the result of a corresponding decrease in the production of small diamonds due to the increased demand for large diamonds (greater than 1 carat). E.g,