Order Of the Bath Tria Juncta in Uno converted button earrings sterling enamel. These unique earrings appear to be a conversion from two gold toned enamel buttons that have soldered gold over sterling silver screw back fastening. The front of the earrings have green enamel leaves with a red enamel doughnut which has Tria Juncta in Uno around the center. The back fastening is stamped sterling. 

The order of bath is a British order that is topped only by knighthood This information was found on its current members: 

The order currently includes the monarch, members of the royal family, foreigners (known as “honorary members”), and the classes of knights—115 Knights or Dames Grand Cross (GCB), 328 Knights or Dames Commanders (KCB or DCB, respectively), and 1,815 Companions (CB)

Fastening only tests positive for sterling silver. 

Earrings measure approx 1 and 1/8th of an inch across.