Cassiterite with Quartz and Zinnwaldite

For me, Cassiterite crystals always add a pang of excitement to a specimen, but perhaps I need to get out more often!  This most delicious miniature certainly does this for me, with four separate, well developed twinned glossy-black Cassiterite crystals embedded between chocolate-bronze books of hexagonal Zinnwaldite Mica crystals and small, 1 to 5 mm milky Quartz crystals.  The Cassiterite twins’ range between 0.7 and 1 cm across and form perfectly defined butterfly twins with lustrous central re-entrant faces.  Zinnwaldite is now no longer classified as a species but is a convenient term for mica within the Siderophyllite and Polylithionite series.  These elegant Mica books attain 1.8 cm and provide an aesthetic foil to the metallic Cassiterite, a tin oxide.  A charming specimen from the famous tin deposit which spans the border between Germany (Saxony) and the Czech Republic (Bohemia).  The locality therefore carries the joint names Cínovec/Zinnwald near to Erzgebirge and Krusné Hory.