Origin of biotite
Examples from the Web for biotite
Historical Examples of biotite
There is some sericite present, also magnetite, resulting from the decomposition of the biotite.
The minerals at contact are quartz, biotite, magnetite and hornblende.
Biotite occurs in some of these rocks, and melanite also is present.
In other minerals the measurements are not quite the same as in biotite.The Birth-Time of the World and Other Scientific Essays
J. (John) Joly
Biotite and all ferromagnesian minerals rarely appear in them, and never are in considerable amount.