Bole

(bōl.) (Min.) An argillaceous earthy mineral, a silicate of alumina generally reddened by oxide of iron. Boles are soft and unctuous to the touch; they adhere to the tongue, and by degrees melt in the mouth, producing a slight sense of astringency. There is a great variety of these earths, from which a red paint may be obtained by calcination. [s. 102]