All our jewelry is made of recycled 925 sterling silver with rhodium treatment. Rhodium hardens the surface and makes the jewelry more durable, shiny and prevents the jewelry from oxidizing. Jewelry with a plating should be treated Care instructionsfully. We dont recommend to use the jewelry when sleeping, showering, bathing or exercisingIn this way, you extend the life of the jewelry. Hilke Collection follows SWEDAC's rules for marking and control and our name stamp is GHI.