An emerald must be predominately green in order for it to truly be called an emerald. If an “emerald” is to blue or to yellow it cannot be classified as emerald. Like ruby and pink sapphire, the color of an emerald must be dark enough for it to be called emerald. If an emerald is to light in color most gemologists and gem labs consider it a green beryl instead of an emerald making it much less valuable. The most valuable emeralds are green to slightly bluish green and medium to medium dark. Emerald gets it color from traces of chromium, vanadium and iron. The higher the chromium or vanadium content of an emerald is the more vibrant the green of the emerald will be. The higher the iron content of and emerald is the more blue the emerald will be. The color of an emerald affects the value of an emerald drastically. A minor difference in color can change the price of an emerald by thousands of dollars. The color of an emerald is often described by the location where emeralds of a comparable color are found. Emeralds with the finest color are commonly referred to as Colombian emeralds. Zambian emeralds are usually slightly darker and a bit more bluish than Columbian emeralds. Brazilian emeralds are typically a lighter green than other emeralds. While these terms may help to convey the color or the quality of the color of an emerald, it is important to know that the emeralds actually come from a specific location or if the term is just being used to describe color because emeralds from certain locations may sell at a premium.