Lead is a chemical element in the carbon group with symbol ,atomic number 82. Lead is a soft and malleable metal, which is regarded as a heavy metal and poor metal. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed to air. Lead has a shiny chrome-silver luster when it is melted into a liquid.
Lead is used in building construction, lead-acid batteries, bullets and shot, weights, as part of solders, pewters, fusible alloys, and as a radiation shield. Lead has the highest atomic number of all of the stable elements, although the next higher element, bismuth, has a half-life that is so long (much longer than the age of the universe) that it can be considered stable. Its four stable isotopes have 82 protons, a magic number in the nuclear shell model of atomic nuclei.
GALENA
Galena is a lead sulfide mineral commonly found in hydrothermal veins; or as fracture filings, cavity fillings and replacements in limestone. Lesser amounts are found in many igneous, metamorphic and sedimentary rocks.
Galena is the primary ore of lead and is often mined for its silver content (silver substitutes for lead within the galena structure). Its perfect cleavage, silver color and very high specific gravity make it very easy to identify.
Galena is the most important ore of lead. Most lead is consumed in making batteries, however, significant amounts are also used to make lead sheets, pipe and shot. It is also used to make low-melting-point alloys. Its use as a pigment has declined as has its use in making solder.
