As shown in the various photos, colored gemstone crystals form in a variety of conditions and locations. And minute differences in the elements that exist within these environments will greatly affect the color and nature of the gem crystals that grow. And indeed, minute impurities that are present in the growing location will guide what colors of gemstones are produced.

Gemstones, therefore, have color because of impurities in the crystal. And virtually every colored stone has a colorless form when it forms without impurities. For example, if you take a colorless sapphire crystal and put a bit of chromium in it, you get a ruby. But take that same colorless sapphire and place some iron and titanium in it, you get a blue sapphire, Take all of the chromium and/or iron-titanium out, you are back to a colorless sapphire. The same applies to beryl. There are large colorless beryl crystals found. But very few that have chromium impurities in them. Because when they do, they are green and are called emeralds. Perhaps the most important point here is that since impurities cause colored gemstones to have their color, they also cause colored gemstones to have.....inclusions. Meaning that for most colored gemstones you will rarely find a completely flawless stones. So always be sure to look for the finest color when shopping for colored gemstones, and make the clarity of the stone secondary.