Johannes Tölkeri /Иоган Телькери/ (b. 1841). In 1857 he came to St. Petersburg and studied under Henrik Hedman. In 1861 he became an apprentice, and around 1870, a goldsmith. According to Postnikova-Loseva he worked until the 1880s. But in reality maker's marks I.T., IT, J.T or JT are found on silver items up until 1908.
Source: Marina Mikhailovna Postnikova-Loseva Index of Russian marks on products made of precious metals of the 17th-20th centuries/Марина Михайловна Постникова-Лосева Указатель русских клейм на изделия из драгоценных металлов XVII-XX вв.
Workshop marks.
1870.
Late 1870s/early 1880s.
1904-1908.
Silver badge type 1894.
Silver, enamel.
Size 30.9 x 30.8 mm.
Weight 12.96 g.
Marked with a barely readable maker's mark "IT".
Source: Marina Mikhailovna Postnikova-Loseva Index of Russian marks on products made of precious metals of the 17th-20th centuries/Марина Михайловна Постникова-Лосева Указатель русских клейм на изделия из драгоценных металлов XVII-XX вв.
Workshop marks.
1870.
Late 1870s/early 1880s.
1904-1908.
Silver badge type 1894.
Silver, enamel.
Size 30.9 x 30.8 mm.
Weight 12.96 g.
Marked with a barely readable maker's mark "IT".