Galena is the greatest ore of lead, and it contains mostly lead. Lead has been extracted from Galena for hundreds of years. Certain places of the mineral is very rich in silver, some places of Galena may contain as much as 20% silver. The chemical formula for Galena is PBS. It is made up of lead and sulfur but it may contain other elements such as silver, Arsenic, Antimony, and Copper. In the United States galena is found in Kansas , Missouri, Montana, Oklahoma, Utah and Wisconsin. Small deposits can also be found in Idaho. It's color is steel- gray and when It is streaked it is also steel gray. Galena is known for it's perfect cubes, cleavage, softness and heaviness. It's hardness is 2.5 to 2.75 and it's specific gravity is 7.58. Galena forms many interesting crystal shapes. Galena, freshly cleaved shows a strong metallic luster, but they can turn somewhat dull after being exposed to air. The tarnish can be washed off by scrubbing the mineral with soap and water. It's easily damaged and well formed crystals may break off into smaller crystals if just put under a little bit of pressure.