Ferrisicklerite Li([Fe.sup.3+], [Mn.sup.2+])P[O.sub.4]
Compact to micaceous masses of ferrisicklerite form irregular replacements of heterosite along fissures.
Black, dense seams cutting heterosite have been found to contain ferrisicklerite, lithiophorite, cryptomelane, [Gamma]Mn[O.sub.2] and perhaps other intimately intergrown manganese oxides with veinlets of quartz and/or variscite.