Galena 

You will receive 1 piece of crystal, the total weight of the piece will be at least the amount quoted in the variation.  Each piece has it's own unique shape and internal markings, for this reason the item received may differ slightly from those shown in the photograph.

Galena is the principle ore of lead. Although lead is normally extremely flexible, the sulfur content of galena makes it extraordinarily brittle and reactive to chemical treatment. Wash hands after handling and do not ingest.
 
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.
 

Lead ore deposit
 

Galena deposits often contain significant amounts of silver as included silver sulfide mineral phases or as limited solid solution within the galena structure. These argentiferous galenas have long been the most important ore of silver in mining. In addition zinc, cadmium, antimony, arsenic and bismuth also occur in variable amounts in lead ores. Selenium substitutes for sulfur in the structure constituting a solid solution series. The lead telluride mineral altaite has the same crystal structure as galena. Within the weathering or oxidation zone galena alters to anglesite (lead sulfate) or cerussite (lead carbonate). Galena exposed to acid mine drainage can be oxidized to anglesite by naturally occurring bacteria and archaea, in a process similar to bioleaching.
 
Galena deposits are found worldwide in various environments. Noted deposits include those at Freiberg, Saxony; Cornwall, The Mendips, Somerset, Derbyshire, and Cumberland, England; the Madan, Smolyan Province, Rhodope Mountains, Bulgaria; the Sullivan Mine of British Columbia; and Broken Hill, Australia. Galena also occurs at Mount Hermon in Northern Israel. In the United States, it occurs most notably in the Mississippi Valley type deposits of the Lead Belt in southeastern Missouri, and in the Driftless Area of Illinois, Iowa and Wisconsin. The economic importance of galena to the early history of the Driftless Area was so great that one of the towns in the region was named Galena, Illinois.
 

Galena uses
 
One of the oldest uses of galena was as kohl, which, in Ancient Egypt, was applied around the eyes to reduce the glare of the desert sun and to repel flies, which were a potential source of disease. 
 
Galena is the primary ore of lead which is mainly used in making lead-acid batteries; however, significant amounts are also used to make lead sheets and shot. Galena is often mined for its silver content (e.g. the Galena Mine in northern Idaho).
 
Galena is a semiconductor with a small bandgap of about 0.4 eV which found use in early wireless communication systems. For example, it was used as the crystal in crystal radio sets, in which it was used as a point-contact diode to detect the radio signals. The galena crystal was used with a safety pin or similar sharp wire, which was known as a "cat's whisker". Making such wireless sets was a popular home hobby in Britain and other European countries during the 1930s. Derbyshire was one of the main areas where galena was mined.
 
Scientists that were linked to this application are Karl Ferdinand Braun and Sir Jagdish Bose. In modern wireless communication systems, galena detectors have been replaced by more reliable semiconductor devices, though silicon point-contact microwave detectors still exist in the market.