A specimen from what has to be my favorite find from my recent Peru trip-- a group of tetrahedrite crystals perched on quartz.  The positioning of the tetrahedrites makes for a particularly beautiful specimen.

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.  Flat on the back, so it can only be displayed as shown.