This gray with a touch of brown is quite transparent for its darker tone value. It came from Thailand and was probably heat treated. I have enough similar material to feel that this color and saturation occurs in nature, but it is not that common. I am always on the look out for good natural grays, even though I don”t think that you can tell a heated one from a natural one. I just like to stay natural, when I can. This oval is eye clean and weighs 6.09 carats.