Galena, sphalerite and pyrite. Navan, Ireland
250µm
Galena (white, top left) has triangular pits (black, centre top) due to plucking along the perfect (100) cleavage and is intergrown with sphalerite (light grey). Euhedral quartz (dark grey), showing a prismatic section (centre) and basal section (centre), occurs within sphalerite and has a lower reflectance than dolomite (small rhomb, centre right). Sphalerite inclusions occur in both gangue phases.
Polished block, plane polarized light, x 80, air
