Leonard James Spencer

“ Seybertite, Brandisite and Xanthophyllite are closely allied species consisting of basic magnesium, calcium and aluminium silicate, and have been regarded as isomorphous mixtures of a silicate (H2CaMg4Si3O12) and an aluminate (H2CaMgAl6O12) . Seybertite (the original clintonite) occurs as reddish-brown to copper-red, brittle, foliated masses in metamorphic limestone at Amity, New York; brandisite as yellowish-green hexagonal prisms in metamorphic limestone in the Fassathal, Tirol ”

“ It occurs as isolated scales scattered through schistose rocks and phyllites of dynamo-metamorphic origin. The ottrelites of the phyllites and ottrelite-schists of Ottrez and other localities in the Belgian Ardennes is a manganiferous variety of chloritoid, but owing to enclosed impurities the analyses differ widely from those of typical chloritoid. ”