A compact variety of diamond, occurring naturally in granular aggregates and used as an abrasive in drill bits, saws, and gem-cutting wheels. It occurs in ultrabasic, igneous, breccia pipes, particularly in southern Africa.
科学参考收录了60776条科技类词条,基本涵盖了常见科技类参考文献及英语词汇的翻译,是科学学习和研究的有利工具。