《天工开物·中篇·陶埏》
无名异不藏在深土之下而是浮生在地面，最多向下挖土三尺深即可得到，各省都有，也分为上料、中料和下料三种，使用时要先经过炭火煅烧。
此物不生深土，浮生地面，深者掘下三尺即止，各省直皆有之。亦辨认上料、中料、下料，用时先将炭火丛红煅过。
Wumingyi does not hide under deep soil but floats on the ground. It can be obtained by digging the soil at most three feet deep. It is found in all provinces and is also divided into three types: top, middle and bottom. It must be roasted over charcoal before use. .