Linda - IMHO that is one of the prettiest patterns made. Flower Garden and Butterfly can be found from time to time but is not readily available. It was made in the 1920's by the US Glass company. It came in pink, blue, teal, green yellow, clear, amber and scarce black. Many pieces were made. I have never heard of it in amethyst. Are you sure of the pattern name?
Reyne Vintage Glass
http://members.aol.com/VintGlass
Has anyone ever seen the Flower Garden and Butterfly pattern made in