I've had small turquoise donuts kicking around for years...I tend to buy items with no particular project in mind. And when it comes to stones like turquoise, the more matrix it has the better! Here I've paired it with black onyx to compliment the turquoise. Tube riveting the turquoise in place was a bit of a challenge due to the shape of the recessed area...yet somewhat easy. Once everything was in place, I dipped it in liver of sulfur!