title: Biotite flakes: alteration by chemical and biological treatment.
abstract: Biotite alteration under acid conditions proceeds differently from the generally accepted pathway of transformation to vermiculite in which hydrated cations cause interlayer expansion, resulting in a dark-colored peripheral band on mica particles. Acid solutions of synthetic or biologic origin remove octahedral ions, leaving a fragile matrix of amorphous material.
authors.forename: J R
authors.initials: JR
authors.lastname: Boyle
authors.forename: G K
authors.initials: GK
authors.lastname: Voigt
authors.forename: B L
authors.initials: BL
authors.lastname: Sawhney