Now General Electric have gone one better than nature and made a diamond purer than the best quality natural diamonds.现在通用电气公司已经制造出了巧夺天工的钻石，其纯度比最好的天然钻石还要高。The sample's density is a measure of its purity.样品的密度是其纯度的一个计量单位。They assayed the gold to determine its purity.他们对黄金的纯度进行了鉴定。