The collection collects 13.000 samples. Of the original collections of the Technical Institute 'A. Zanon' and the Institute of Toppo Wassermann remain only part of the specimens, while others come from collections of important scholars such as Feruglio, Gortani, Colbertaldo, Morgante or various donations, including that of S.A. Miniere di Raibl, and the most recent of the Spivach family.
The most significant petrographic collection is that of prof. Michele Gortani. It includes almost 1500 samples of various areas of Friuli and covers the entire stratigraphic series present in the Region from the Lower Paleozoic to the Cenozoic.
In recent decades, numerous finds have been added, the result of studies and research in Friuli, carried out by operators and collaborators of the Museum.