Groutite

Groutite is a rare manganese hydroxide that is known to form excellent crystallised specimens at the Emilie mine, also known as Bülten-Adenstedt mine, in the Peine district of Lower Saxony, Germany.  The Groutite forms a mix of hemispherical and oblate botryoidal surfaces over which silver black crystals of a different habit of Groutite cover a roughly 3 x 2 cm area.  These crystals are tabular with rounded terminations and appear to be built from masses of parallel, highly lustrous Groutite fibres.  A quite gorgeous miniature of this rarely encountered manganese species.