Buhrstone

[bә:stәun]

解釋/意思:

(n.) A cellular, flinty rock, used for mill stones.

校對:罗尼

解釋/意思:

n. a variety of quartz containing many small empty cells which give it a peculiar roughness of surface particularly adapting it for millstones.—Often Burr′-stone.

手打:西尔维亚