Antique frog figurine

I bought this at an auction in the south of England about 20 years ago. I was the only bidder, but it seemed intriguing. Does anyone know about its provenance? On the underside it is marked with a stylised "F" St Petersburg and dated 1882. It is green, textured with a sparkle under artificial light and is very pleasing to the touch. The design is interesting from every side. The frog has a crystal eye and a beetle on the leaf. It weighs 103g (3.6oz).