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).

Buildings/Construction

 * The City of Brass made heavy use of this metal.
 * In Memnonnar, the domes and minarets that topped the buildings were inlaid with brass.
 * Brass was one of the many precious metals that decorated the bricks of the Ziggurat of Eternal Victory.

Weaponry

 * Cultists who worship Baphomet have been known to decorate their altars with brass weapons.
 * Orthons have been known to carry crossbows made of brass.

Magic Items

 * The Farseer of Illusk was partially made of brass.
 * Harvyn's Ring
 * Helms of underwater action were forged from brass. 
 * Rings of dragons were brass rings highly prized by members of the Cult of the Dragon.
 * Rings of flying were made with brass lining the edges.
 * Purple dragon rings were always crafted from brass.
 * The serpent rings worn by worshipers of serpent and reptilian deities were fashioned from brass.
 * Staffs of entrapment were traditionally made by the Netherese with brass.

Spells

 * Early versions of Bigby's clenched fist required a pair of brass knuckles for casting the spell.
 * A brass cube was one of two options for material component when casting the spell Darsson's music box.
 * Detect scrying required a miniature brass hearing trumpet for casting the spell.
 * Dreamspeak required a bell made of either brass or silver for casting the spell.
 * Find familiar required a brass brazier for casting the spell.
 * Horizikaul's versatile vibration required a hollow brass cone as a focus.
 * Hornung's surge selector required a brass spinner for casting the spell.
 * Brass tuning forks were required when using a plane shift spell to enter the Para-Elemental Plane of Magma.
 * The Great Brass Gate was the portal though which the noble efreeti Memnon entered the world of Toril to found Memnonnar.

Currency

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