All of our pieces are cast in either .925 sterling silver or 14K gold. We can cast in 18K gold by special order. Our sterling silver pieces are plated in platinum to prevent tarnishing, which also lends a beautiful bright finish to our pieces. Our yellow gold plated pieces are cast in sterling silver then plated in 14K yellow gold.  All plated finishes wear off over time. We recommend taking off your pieces when swimming in pools or salt water, which will help to prolong the life of the plating.