《天工开物·下篇·珠玉》
剖玉所用的沙，在内地出自顺天府玉田和真定府邢台两地，此沙不是产于河中，而是从泉中流出的细如面粉的细沙，用以磨玉永不耗损。
中国解玉沙，出顺天玉田与真定邢台两邑，其沙非出河中，有泉流出，精粹如面，藉以攻玉，永无耗折。
The sand used to cut the jade comes from two places in the mainland: Yutian of Shuntian Prefecture and Xingtai of Zhending Prefecture. This sand is not produced in rivers, but rather is a fine sand like flour that flows from springs, and using it to polish jade never wastes it.