Verde duro di Massa e Carrara, most probably from the Apuan Alps of Italy
Geological description:
Coarse-grained diorite.
Comments:
A small square 18th or 19th century tablet of this stone in the Naturhistorisches Museum Wien is labelled 'verde duro di Massa e Carrara', indicating this stone is from the Apuan Alps.
References:
Other examples: Naturhistorisches Museum Wien T2-6-3 G7366 [1898] 'serpentin (verde duro di Massa e Carrara)'.