A specimen from what has to be my favorite find of the trip-- if it were not for the quartz, it would be easy to mistake this for one of the old Tsumeb tennantites (the arsenic rich member of the tetrahedrite group)
This piece is a HUGE single crystal coated with tiny bournonites, with a small quartz cluster clinging to one corner.
There is a slight blue-greenish dusting on the tetrahedrite that makes for a particularly aesthetic color combination-- I do not know what exactly that is, but it is certainly a copper mineral.
The tetrahedrite is coated with tiny crystals of bournonite, and comes from a find made within the last several months. I saw a couple flats of this material in Tucson, but all were off matrix and had major damage issues. I saw one good lot of specimens while in Peru, this piece comes from that group.