In the entire area of the deposit, apart from pyrite, only gypsum, chlorite and some manganese minerals have been found.
Pyrite occurs almost exclusively in cubic form and very rarely in cubo-octahedral crystals.. Also pyritohedra. Some specimens with beveled edges also come from Navajún.
The sizes are between the millimeter and 20cm. edge, between which all intermediate measures can be given.
With great care, matrix blocks are extracted from the mine that are later transferred to the workshop where an artisan process begins to shape the pieces, cleaning and classifying them.