There can be a lot of color variations in Turquoise. The pieces that I remember seeing usual was not one color over the hole piece. They would have some other shade mixed in.
I like the Jade idea myself.
Are you sure it is a stone and not plastic? I remember in the 70's there use to be a lot of fake Turquoise in heavy plastic and you tested by heating up a pin and seeing if it would go through the stone.
If it is Jade then it is a stone and the pin should not harm it. If you are worried about damaging the ring take it to a jeweler and they can readily identify the stone.