If I’m not mistaken, I saw a very similar artifact in the Hermitage back when St. Petersburg was still called Leningrad. Somewhat smaller, as I recall. Unfortunately, I think I’ve only been back to the Hermitage once since then, and, on the day that I was there, the museum was horribly crowded and I had only a short time. But I don’t think I’m wrong. I remember taking a photograph, but that was many years and several moves ago, and I have no idea where to find the photo now.