Iron sukashi tsuba decorated with chrysanthemums. Based on examples I have seen NBTHK usually attribute this type of tsuba to Heianjo School. However Heianjo tsuba have inlay made of copper and brass. This tsuba has copper inlay that has been gilded. Which is not common.
In my opinion it looks like a chrysanthemum, however in reference material I found opinions differ. Sukashi is described as wheel (Kuruma) or amida, referring to rays surrounding amida buddha head. Copper inlay is described as seigainami, which is a wave design pattern.
Some inlay missing
Size: 74 mm x 71 mm x 3 mm
Similar tsuba are for sale on ebay:
https://www.ebay.com/itm/Scarce-Iron-78mm-Saotome-Heianjo-48-Spoke-Tsuba-with-NBTHK-Tokubetsu-Papers/383830597055?_trksid=p2485497.m4902.l9144
And shibuiswords:
http://www.shibuiswords.com/tsuba.htm
(look for "Taken from GAI SO SHI Study Collection")