sterling silver, copper
Silver, oh silver. This lustrous white metal is amazing - more reflective than gold, more conductive than copper and just plain gorgeous. When used for jewelry, silver is mixed with copper or zinc to provide more durability and reduce tarnishing. Fine silver is 99.9% silver while sterling silver is 92.5%. Other alloys are used for specific processes, such as reticulation (80% silver). All silver will tarnish over time, but can be easily cleaned and polished.
Unlike most metals which must be refined from ores, copper occurs in nature ready to be used. It was the first metal humans learned to smelt, the first we learned to cast into shapes and the first we mixed with other metals to form alloys. We've come a long way in the last 10,000 years, but we still love the red-orange luster of a nice shiny piece of copper!