
Piece of Green Granite Erbetta

Piece of green granite Erbetta. 1 of 5 specimens used to show the results of a process for polishing marbles, invented by A. Gath of Rome about the year 1825, and applied to reflectors for astronomical purposes.
Piece of green granite Erbetta. 1 of 5 specimens used to show the results of a process for polishing marbles, invented by A. Gath of Rome about the year 1825, and applied to reflectors for astronomical purposes.