Marcasite & Garnet Sterling Pendant Brooch

A central faceted and prong set garnet surrounded by smaller garnets set in sterling silver set marcasite.  Along with a firm roll over safety catch there is a pendant bale which gives the opportunity of putting on to a chain to wear as a pendant. No signature, and no known provenance but tests for silver and recently purchased via an estate sale USA.  Measurement across the brooch is 3cms. I would think not a long history. A timeless piece,  in perfect condition. Free express postage within Australia.