Copper (Cu #29) (Latin: Cuprum) is the next element on the periodic table for my APEX mineral collection.Wikipedia Copper
Copper Minerals - There are lots of Copper minerals.
Together with Caesium and Gold (both yellow), and Osmium (bluish), Copper is one of only four elemental metals with a natural color other than gray or silver.
This column of the Periodic Table (group 11) is my favorite. It contains Copper, Silver, and Gold. These metals are all "pretty" and are great for investment. Copper is cheap enough that it can be used for common manufactured objects. Silver gets more expensive but has the right value for jewelry and electrical applications. Gold gets more expensive and has the right value density for storing lots of value in bank vaults.
These metals do not oxidize easily and are the best metals for electrical conductivity and thermal conductivity.