How do gemstones get their color?

If you have ever wondered what makes a ruby red vs a sapphire blue, or better yet why there are so many different hues to a stone, such as a ruby. Why a ruby can go from pink to blood red and why are some clear while others are opaque?  Which stone is the better one? Lets be honest, not all stones are created equal!  This can make shopping and comparing very difficult for the consumer. This is why I highly recommend shopping with a reputable jeweler, you can do all the research in the world but a good jeweler can spot an inclusion or imperfection and know if it is something that you should be concerned with or if it should be considered a beauty mark. Most customers know the four C's when it comes to diamonds, but they have never considered how those same guiding principles should be applied to precious gemstones too.  What makes a precious stone vs a semi-precious stone? Its all about market demand, Mother Nature can only produce so much gem quality stones.  When consumers buy more sapphire, ruby and emeralds than what Mother Nature can produce in gem quality, lapidary shops will cut and polish varying degrees of quality for consumers to choose from, thus the price variable. Semi-Precious stones such as an amethyst, topaz, garnet or peridot, may have a few color options but for the most part, Mother Nature makes enough gem quality to meet market demands without having to use lower grades. Now, back to the main question, why is a ruby red... I am attaching a great read for all curious minds, I hope you enjoy! 

 http://www.compoundchem.com/2014/06/29/what-causes-the-colour-of-gemstones/