A common mineral form of lead is galena, lead sulfide (PbS). In the sample shown, the galena crystals are formed in a bed of quartz. The sample is about 4x4 cm and is from Neudorf, Germany.
Galena is a noticeably dense mineral, having a density of about 7.6 gm/cm3. It has a metallic luster.
The samples pictured here are on display at the Smithsonian Museum of Natural History.