(Όρος Βερτίσκος, Πολυδένδρι - Κολχικό, Θεσσαλονίκη,)
Stratabound tourmalinite bands within metapelites (boron-rich aluminous clay precursors).
The metasedimentary pelitic/psammitic schists (Vertiskos formation) are associated with migmatitic gneisses and intruded by pegmatites.