Geology

     Talc , Mg3 [(OH2) / Si4O10] is a mineral which always forms at other rocks’ expense. The talc from Bagnada formed a long time after its embedding rocks, which are dolomitic marbles.  The marbles from the Dolomites are a kind of white metamorphic rock that looks like sugar and which formed from the Triassic sediments - of calm and not much deep seas - transformed by metamorphism.

During the last phases of the alpine orogenesis a system of fracture took place and determined the process of talc formation through chemical reactions. The dolomitic marble provided magnesium; silicon was supplied by aqueous solutions rich of silicon oxide of metasomatic origin (not of hydrothermal origin as you can read in some brochures!)

There are two veins of talc along fractures in the direction NE- SW; their thickness can vary from 10 to 20 m. Talc is generally schistose, white and sometimes can contain some nodules of solid and greenish tremolite, which is the remains of a previous metamorphic phase and of a higher grade . Talc is greasy and its thickness is 1 on the Mohs scale. The  quartziferous vein of Dosso dei Cristalli has no genetic connection with the talc ore body it cuts and it is younger.

The researches carried out in laboratory and the study of paragenesis allow to determine that the talc formation of Bagnada took place at a temperature of 350°- 500° C. The temperature of the alpine metamorphosis is higher and it can confirm that the talc ore body is very young.