Galena, also known as galenite and lead-glance is a natural mineral composed of lead sulfide (PbS). It is the most important ore of lead and deposits are found worldwide. It occurs as dull grey to silvery grey cubes or octahedral crystals, sometimes with skeletal surface. Its crystal symmetry is isometric hexoctahedral. The substrate is quartz here seen in a habitat of small prismatic crystals. Sample is from Madan in Bulgaria, actual width is 17 cm.