This is the cluster of galena crystals. Dimensions: 2.8 x 2.0 x 1.2″ (7 x 5 x 3cm). Weight — 10.6oz (301 grams). Origin: Russia, Dalnegorsk.
Some information about galena:
Galena, also called lead glance, is the natural mineral form of lead(II) sulfide. It is the most important ore of lead and an important source of silver.
Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite.
One of the oldest uses of galena was in the eye cosmetic kohl. In Ancient Egypt, this was applied around the eyes to reduce the glare of the desert sun and to repel flies, which were a potential source of disease.