Big clear stone

Hello I’m looking at some stones and thought I would check out some stones that I bagged years ago, this is a 4.05 ct big clear stone that I just assumed was a CZ or something, but just been listening to a girl on YouTube talking about white sapphire, I have many white stones but only really look at the coloured ones, I guess he would have kept the diamonds. But always thought I might find some mossianites but didn’t consider white sapphire