925 silver necklace with polished stones

It hangs 2 inches. This piece is beautiful. I don’t know the name of each stone. The small round one is most likely amethyst. The blue triangular one might be topaz. The top stone has me stumped . It shimmers purple and greenish to me and is one inch wide. I am selling this for a friend and may buy it for myself because I really love this one. So artistic. There is a logo on the back which is a b in an oval. Stamped 925.