The Blue Gem mine was at one time located deep underground, accessed by tunnels as deep as 800 feet. This is of interest because the Blue Gem Mine and the Bisbee Mine in Arizona are the only two mines (of which we are aware) where turquoise was found that deep in the earth. Blue Gem turquoise is a rare, valuable, and historic American treasure. Quality Blue Gem Turquoise has been gifted with a wide range and variety of colors, from a beautiful sky blue to an aqua blue-green, not unlike parts of the Mediterranean Sea. Because Blue Gem turquoise is very hard, a high polish is associated with this stone, and unlike most turquoise, it won't easily change color. This turquoise has a unique character and many different looks all of which are striking, full of wonder, and pleasing to the eye.