Copper

Copper is a precious metal that is used in Faerûn as the baseline of most currency. When used as currency, it is usually cast into copper pieces (cp) of a standard weight.

Worth
Most coins in Faerûn work off of the silver and gold standard, with copper pieces (cp) being worth 1/100th of a gold piece (gp) and Silver pieces (sp) being worth 1/10 of a GP. Electrum coins are worth 50 cp (1/2 gp), and platinum coins are worth 500cp (5gp) in 1st and 2nd edition and 1,000cp (10gp) in 3rd and 4th edition.

Each coin is approximately 30.6 mm in diameter and weighs approximately 9 grams each (or 50 to one pound).

Conversion
Simplified: 1000cp = 100sp = 20ep = 10gp = 1pp