Electrum

Electrum was a naturally occurring silver-gold alloy with half the value of pure gold: 1 electrum piece (ep) was worth 50 copper pieces (cp), 5 silver pieces (sp), 1/2 of a gold piece (gp), or 1/20 of a platinum piece (pp).

A standard electrum coin was approximately 30.6 mm in diameter and weighed approximately 9 grams apiece (or 50 to one pound). As a bulk trade good, it was worth 25 gp per pound.

Value and terminology
Most of Faerûn used "standard rates of exchange for coinage," based on the silver and gold standard, with 1 cp worth 1/100 gp, 1 sp worth 1/10 gp, 1 ep worth 1/2 gp, and 1 pp worth 10 gp. .

Electrum coins adopted various names throughout the Realms.
 * Amn minted coins called centaurs or decimes
 * Calimport minted centarches, tazos, or zonths
 * Cormanthyr minted thammarchs
 * Cormyr minted blue eyes
 * Sembia minted electrum coins called harmarks or electrums
 * For a time, Sembia evidently went off the silver and gold standard, and they minted electrum coins called blue eyes, valued at 5 gp apiece
 * Waterdeep minted moons, or harbor moons
 * Silverymoon minted special coins called electrum moons

Throughout the Western Heartlands, most electrum coins from abroad were called blue eyes regardless of origin.

There are two special coins valued more within the city they were minted in:
 * The original shining blue crescent-shaped electrum moon of Silverymoon, a coin worth 1 ep throughout the Realms but twice that within the city itself.


 * The harbor moon of Waterdeep, a cresent shaped Waterdhavian coin made of platinum, inset with electrum, and punched with a central hole. It was used for bulk transactions, one coin being worth 50 gp within the city of Waterdeep and worth 2 gp –30 gp anywhere else.

Electrum currency was generally rare and not available in the Land of Fate.

Other uses
The spell Khelben's warding whip used a pinch of powdered electrum as a material component.

The spell Leomund secret chest could use a chest fashioned from bronze, copper, or silver with fittings of electrum or silver.

Magical morning stars known as storm stars were crafted from electrum-plated steel. They could unleash a chain lightning effect.

An electrum mounting allowed witherite to be worn as a protection to necromantic attacks.

Two notable tomes—The Chambeeleon and The Tome of the Unicorn—had electrum pages, with the latter also having electrum covers.

If one of the twisted bands of a shoonring was made of electrum, this usually indicated that the ring contained multiple powers and enhanced the effects of the magics involved.