chloritoid Min.
(ˈklɔərɪtɔɪd)
[f. as chloritic a. + -oid. Named by Rose, 1837, from its resemblance to chlorite.]
A foliated hydrous silicate of alumina and iron, varying in colour from greenish black to gray; also called chlorite spar.
| 1844 in Dana Min. 523. 1873 Proc. Amer. Phil. Soc. XIII. 399 Chloritoid..has been observed at many of the corundum localities. |