Galena, or lead sulphide (PbS), is a shiny grey mineral and the main ore of lead. Also known as Silver-Lead, it can be found in Carboniferous and Palaeozoic rocks around the world. In Britain it is found in Derbyshire, Wales, Upper Teesdale, Weardale, Cornwall, Cumbria, and the Yorkshire Pennines.

Use of this mineral can be traced back to c.3,000BC, when the Ancient Egyptians used it as a kind of cosmetic known as Kohl applied around the eyes. The dark marks it produces played the dual role of both reducing the glare of the powerful desert sun, and also as a fly repellent which helped reduce the instance of disease. Though it was used in this manner by the Egyptians, being an ore of lead it is also harmful to health causing lead poisoning. Galena is also a semiconductor (like silicon in today’s computers) and was used to detect radio signals in early receivers as a point-contact diode.

Mining for lead in Britain probably pre-dates the Roman occupation, but it was during their tenure here that the mineral appears to have first been extracted on a large scale. In many places small areas of Roman workings can still be found today. The Romans located the ore by looking for a small white flower, Spring Sandwort (Minuartia verna), also known as Leadwort; This flower grows on land heavily polluted by lead and other associated heavy metals. Where the Romans noticed this plant growing they would scrape back the soil and grass to locate the vein or rake of lead which was then extracted and smelted.

Lead is often found in hydrothermal veins and is associated with silver, pyrite, calcite, fluorspar and barites, all of which are useful by products known as gangue minerals.

The images above show a large boulder with Galena, the flower Spring Sandwort, and a fist-sized sample of Galena with flourite.