Items made from precious metal, silver, palladium, platinum, pearls or precious stones of <a href=https://nanojournal.ifmo.ru/en/articles-2/volume4/4-3/mam-12/paper15/>https://nanojournal.ifmo.ru/en/articles-2/volume4/4-3/mam-12/paper15/</a> and intended wearing as personal jewelry.