Sphalerite, galena and pyrite. Navan, Ireland
500µm
A euhedral crystal of galena (white, centre) has cleavage pits and lies within a botryoidal sphalerite (light grey) overgrowth, which itself occurs within less well polished sphalerite that contains abundant fine-grained pyrite (yellow-white, right centre). Black areas are polishing pits.
Polished block, plane polarized light, x 40, air
