Tennantite-Tetrahedrite epitaxial on Chalcopyrite & Sphalerite on Quartz

Item Description

A very unusual and rich large two-sided combination rib from this noted locale. Lustrous to matte-finish tennanite-tetrahedrite epitaxically coats well-placed compound chalcopyrite and sphalerite crystals to 1.5 cm on the quartz crystal rib. You can see the chalcopyrite and sphalerite on some of the crystals and especially on the broken crystals. Both sides have rich coverage of crystals. A similar specimen is figured on Page 602 of the El Cobre Mine article in the current Mineralogical Record Mexico Special Issue VII. GOOD timing! A fine, large and rare two-sided specimen. These came out around 1970.