Blue Tiger Eye History, Meaning, Properties, Benefits & How To Use The blue tiger eye gemstone is a bluish-green to bluish-grey stone that is made up of microcrystalline quartz, or in other words, chalcedony. But it is different from most of the chalcedonies – the blue tiger eye is gemologically classified as a rock and not a mineral. Blue Tiger Eye is created in nature as a result of pseudomorphosis. What is pseudomorphosis? Well, it is a stone replacing a part of another mineral over a long period of time. When microcrystalline quartz goes through pseudomorphosis, blue tiger eye is created.