What does the term ‘implant grade jewellery’ mean?
“Implant grade jewellery” is manufactured from the same materials used in medical implants. In order to be considered implant grade, the metals in this jewellery must meet ASTM specifications. The American Society for Testing and Materials, or ASTM, is one of the largest voluntary standards development organizations in the world. Their system of specifications provides assurance of the quality, make-up, testing and reliability of materials in the marketplace.
See ASTM material specifications for stainless steel here.