Brass

Brass was an alloy of copper and zinc.

Applications
Brass was used for decorative items, moving metal parts (locks, gears, valves. etc.) and musical instruments (for acoustic properties).

The find familiar spell required a brass brazier for casting the spell.

Magic items such as a ring of dragons, purple dragon ring, and staff of entrapment were all made of brass.

Brass tuning forks were required when using a plane shift spell to enter the Para-Elemental Plane of Magma.

Currency

 * The Waterdhavian taol was worth 2 gp in Waterdeep, but little elsewhere.
 * Gond bells worth 10–20 gp.