I use gold casting alloy as decoration in the following tutorials:
Wave Bangle
Forged Coil Cuff
Yellow Gold Alloy is what goldsmiths add to 24k gold to make it into different karats. I like the color of it and its price compared to gold itself. It is available in 1oz packages. The alloy is mixed in size.

Because this item costs twelve dollars to ship with a tracked envelope it will be sent by regular mail. This can take 5-15days depending on where you live.