Gr52-this magnificent specialty cut Tanzanian sapphire has been declared by "Gemval" to be a natural color change sapphire. their light tests show that it is a strong yellow/green in daylight and a moderate orange in incandescent light. it is a fan shape & the cut is very good.this stone would be excellent in jewellery or would go well in somebody's collection.these stones are very difficult to obtain, especially over a carat. this stone comes with its evaluation certificate from Gemval(which can be viewed in the photos).(in the video, the gem goes a sparkly pink when a uv laser is pointed on to it, this only seems to happen with this kind of rough.) please feel free to check Gemvals credentials. far nicer in reality