Fossil Resin from East Africa. It has a high point of fusion and produces a very hard film, that is also bright and lasting, but not easily removed in case necessary. See Copal.
note: De Mayerne Theodor Turquet, Pittura scultura e delle arti minori. 1620-1646, a cura di Simona Rinaldi, Anzio, De Rubeis 1995.