For more than a century, the Four Peaks mine in Maricopa County, Arizona, has produced gem-quality amethyst from crystal-lined or crystal-filled cavities and fractures in a brecciated quartzite host rock.

了解紫水晶的坚固性，以及如何保养紫水晶首饰。

紫水晶是石英矿物的紫色类别，而且一提到紫色宝石，人们通常联想到的便是紫水晶。

本文摘自《宝石与宝石学》(Gems & Gemology) 1991 年秋季刊，是《宝石与宝石学》(Gems & Gemology) 外部发表的重要宝石学相关文章的摘要汇编。