Sapphires are amazing for many reasons, including the diversity of colours they may have, the phenomena that may have, and the parts of the world where they may occur.
On average, sapphires are thought to be blue, but they really can be any colour except red (red is reserved for ruby of the same mineral).
This gem has several interesting things to note: It is a star sapphire, with needle-like inclusions oriented in three directions causing reflections to form a 6 ray star, plus it changes colour, purple in incandescent light and bluish in daylight, but it also has bubbles that move around in liquid filled inclusions (one of the bubbles disappears when the gem is warmed to hand temperature, and returns when it cools down). The liquid filled inclusions virtually prove that the gem has not been heat treated, the presence of the star due to inclusions helps to prove it (these would be damaged during the heating process). This sapphire likely originates in Sri Lanka. Lot 244 in the upcoming November 24th 2013 Dupuis Auction. For more information go to: http://bit.ly/HYXndu