Medieval gold annular brooch with sapphires

A Medieval gold annular brooch set with sapphires.??

French or English, 13th century.

Measures 3.3 x 2.4cm.

Weighs 5 grams.

Provenance: Private English Collection

The brooch of unusual triangular form is engraved with flowers, the corners each set with sapphires (one missing).
The vacant loop which protrudes from the inside was probably intended for a safety chain.