INTRODUCTION Brass is an alloy (a homogeneous mixture containing two or more solids) of primarily two metals: zinc and copper. Many different brass compositions exist, as can be seen by the very different colors of brass samples. Due to its range of colors, malleability, and ductility, brass is used in a wide variety of applications such as keys, doorknobs, musical instruments, and electrical switches. Zinc dissolves to form zinc nitrate, which is colorless in solution while copper is converted into copper (II) nitrate, which turns the solution a distinct blue color. Many transition metal ion solutions are colored because the electrons within the metal ions absorb light in the visible region and are excited to a higher energy state.