Postby dognose » Fri Feb 12, 2021 12:48 pm
Hi,
It's silver-plated. The maker was Alexander Katch, a German, who set up a factory in St Petersburg in Russia in the second half of the 19th century and was in business there until at least c.1910. The 'GP' stands for 'Galvano Plated'.
Trev.