I took this clipart image from CLIPS AHOY!
I was searching the Internet to find what to call a medieval mason’s Steinbeil and Steinpickel (axe and pick?) for building Einhard’s basilica at Michelstadt, and came across a history of the gavel. It’s on the site of The Gavel Store (‘the largest and the best selection of gavels in the world’). Apparently they have a masonic past, inter alia.
I must say I know gavels only in the U.S. judge context. I would say an auctioneer has a hammer. But apparently the term gavel can be used for an auctioneer’s hammer too.
You can get gavels, even in the form of earrings, at For Counsel, and a lot of other – er – stuff for lawyers too.