Calcite on Sphalerite

I just pulled this from my suite of Romanian calcites and am already regretting it. This is a top notch piece in every regard. The bottom half reveals black sphalerites with tiny individualized  clear calcite prisms with trigonal terminations. The density of the calcites bloom into a dense mass towards the top where the outer crystals are highly compounded by later stages of development. They are bright and perfect. No damage noticeable.

Locality: Cavnic, Maramures County, Romania

Composition: calcium carbonate