Heated crystals in metal mounts (a) Felspar E79-'77
Heated crystals in metal mounts (a) Felspar E79-'77, (b) Gypsum E79a-'77, (c) Carbonate of Lead E79b-'77
Heated crystals in metal mounts (a) Felspar E79-'77, (b) Gypsum E79a-'77, (c) Carbonate of Lead E79b-'77