Chalcopyrite (2) Raw Minerals Crystals Stones Rocks Collecting Plexiglas Box

Chalcopyrite 16.6 gr mm 26 x 17 x 14  Raw Minerals Crystals Stones Rocks for Collection, in plexiglas box cm 4.2 x 3.7 x 3.2 h, only a piece, as in photos.
Copper and Iron Sulfide.
Also available tumbled, rough single piece, at this link.

Chalcopyrite is a copper, iron and sulfur mineral belonging to the homonymous group, which crystallizes in a body-centered tetragonal system of chemical composition: CuFeS2.
The color varies from brass to golden yellow, has a hardness from 3.5 to 4 on the Mohs scale. The violet or blue veins are a typical feature of the mineral.
Associated copper minerals include bornite, chalcocite, covellite, digenite, carbonates such as malachite and azurite. Chalcopyrite is rarely found in association with native copper.
Chalcopyrite is often confused with pyrite, although the latter crystallizes in a cubic system and not a body-centered tetragonal system. It is also found in large quantities, rarely in crystalline form, and less brittle. Chalcopyrite is also called "yellow copper" due to its high copper content and its color.
It is found in deposits of volcanic origin of sulphides and in deposits of exhalative sediments formed by the deposition of copper during hydrothermal circulation processes.
It is the most important source of copper. It can be found in many forms, from large deposits such as Timmins, Ontario, to irregular veins, cones in the American cordillera and the Andes. It can be found associated with pyrite nodules in coal beds and disseminated in sedimentary carbonates.
In Italy the main deposit of this mineral, now exhausted, was located in Tuscany, and was exploited by the Caporciano mine.