I obtained the rough for this medium gray oval from Thailand. It has probably been heated and my principal interest was to see if I could tell the difference between heated and unheated tourmaline. I could not tell there was any difference. The gray is a bluish gray and I have similar that are unheated, in my opinion. I still prefer unheated material, but I am not as concerned about the physical properties of heated material. The gray is eye clean, bright and flashy. It weighs 4.29 carats.