The material devoted to research of rather large jewelry collection in the Art Nouveau style, which has been kept in the Russian state depository for precious metals and gems, has been presented. It was collected during last 20 years and scientifically processed. Decorative quality of the collection items, unequalled skill of execution, professional culture and experience of craftsmen of those times deserve the high estimation. Showpieces reflect the life of different stratum of the Russian society at the end of XIX — at the beginning of XX century, their mental world and aesthetic style of the epoch. Scrupulous examination of the collection exhibits allows to estimate its scientific value and to trace development of the Art Nouveau stylistic features in jewelry art on the whole — from dominating sophisticated forms with rich decorations at the early stage to more strict and functional solutions.