Garnets are often equated with red, but can also be orange, pink, green, black and honey brown. Garnet is a generic name for many minerals, each of which is named after its color. 

In the large garnet family, there are two groups that we can define: pyralpites and calcic. Pyralpites have a color due to the presence of iron ranging from brown to red (pyrope: red, almandine: from purplish red to purple, spessartite: orange) while calcic (hessonite: orange/brown, tsavorite: emerald green, dementoid: lime green) owe their color to impurity elements. They can thus be green thanks to vanadium or thanks to chromium, etc.