This is probably a Japanese artefact. The characters are
From a brief Google search, the only record which came up is from a Japanese website (http://www.ezimport.co.jp/product.php?id=t533042480) which no longer is active. The residual archive text in that link says
This is a beautiful circular bronze seal, perfect for calligraphy. The writing says 「緯斎（齋）学（學）書」, doesn't it - beautiful words indeed. The seal's surface diameter is 56 mm, and height is 45 mm.
If your measurements match this, then you've found a residual internet comment talking about your aftefact.