Gold is a precious metal that is used in Faerûn as the baseline of most currency.
Gold is prized by many wizards for it's magical properties. If refined and treated with the right magical processes, gold can become as hard as steel and then used to forge effective armour and weapons. Acid and fire are less effective against said pieces of equipment, though the extra weight tends to make golden armour too cumbersome for all but the most skilled wizards themselves to wear so tends to get sold or given as a gift to those who aren't so much restricted by weighty armours.
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 5gp, and platinum coins are worth 10gp. Gold coins are usually minted circular, without any holes, an eigth of an inch thick and an inch-and-a-quarter in diameter. Any less than that and they are considered by most to be "shaved" and worthless. The metal is valuable to many artisans for its malleability, its aesthetic qualities, and the fact that it does not tarnish or rust.