I am crazy for rings and rocks, and this has to be the perfect combination for me from Switzerland's Mirca Maffi, seen below.
Plastic color by Claudia Correa Noe.
Universal Connections rings (below) from Dialog5.
all above via the always wonderful Carrot Box.
Eleanor Salazar's adorable rings called poolballrings, made from billiard balls. Adorable!
Mark Vaarwerk makes rings from plastic bags and bottles! I love these horn stackable, affordable rings from Old Beads
Two Russian designers, Stas Zhitsky and Sergei Kuzhavsk have created some fun and wonderful rings, Jody Work's O-U Ring Lite from Studio 1am.
Karl Fritsch organic and rough rings
Barbara Uderzo's "Succulent" Ring, sculpture wood, earth, small succulent.