Unheated Blue Sapphire 4.00 caratUnheated Natural Blue sapphire 4. 0 carat Unheated natural blue sapphires in an octagon shape with excellent cutting quality and eye clean clarity are highly desirable. A 4. 0 carat stone of such quality would undoubtedly be a breathtaking centerpiece for any jewelry design, prized for its rarity and beauty. world famous sapphire for Ceylon Blue sapphires all the time