Brass Alloys

Brass, as an alloy of copper and zinc, is used in custom coinage in several forms and is a popular choice. Zinc content within brass alloys can vary and that variance can change the color (as well as hardness) of the resulting alloy. The color can range from somewhat reddish, a yellow gold color, to a silvery color or even a shade of green.

MerlinGold^®, a proprietary brass alloy with a mirror finish developed by Northwest Territorial Mint, has a gold-like surface resulting in a very detailed and proof like coin. Such a coin can have satin lustered surfaces to contrast to a highly reflective background. For a look similar to gold select, but with a base coin color of gold, a MerlinGold^® coin can be selectively plated with nickel, as shown in this Fort Myers coin. An antique bronze finish of this same coin is also shown.

Brass alloys also respond well to antiquing, a process of applying an antique-like finish to the coin surface and selectively buffing the highlighted areas. Such a finish is often termed bronze, though this is not actually a bronze alloy.

Enameling a portion of the coin is another finishing option that can add distinction. Almost any color or combination of colors can be done, with red, white and blue being especially popular. Some enamels can provide a gradation in tone along the enamel edges. The enamel process itself is done after the coin is minted, and is applied by hand by an artist with precision instruments under high magnification.

Brass alloys are generally harder metals than silver or gold and will have better wear properties. In order to selectively plate brass alloys with gold, the coin must first be plated with nickel in order to avoid metal migration, and then it can be completely or selectively gold plated.

The brass metal, as a raw material used by the mint, comes in a variety of forms. Often used from rolled metal, ready for straightening and blanking. It is also available in strips and plates. 230 brass and 260 brass are two common alloys available in which the alloyed zinc differs.

Police Coins is a part of Northwest Territorial Mint, one of the Country’s largest and most respected minters of fine custom coins and medallions.