My choice for the material I used is based on my understanding of preciousness and value. Common minerals such as beach pebbles and quartz are abundant in my immediate environment. They have value to me for their visual uniqueness and attraction not bound to monetary value. I elevate trivial materials into something unique, a proof that simple objects can have layers which are not immediately obvious. The trivial ring is not so ordinary after all.
The placing of value seems to be a judgment made freely by the individual in his or her irreducible subjectivity. 
These materials are quartz from Mt Lofty and Carrickalinga beach pebble
Mt Lofty Quartz set in sterling silver
Carrickalinga beach pebble, sterling silver
Chiastolite from Bimbowrie South Australia