Extremely Fine Toulouse (M) mint Louis XVI Royal France silver ecu coin, larger and heavier than a US silver dollar.
Certified by PCGS to XF 40, dark toned, oblique lighting used to highlight details, resulting in lighter images than actual. This approximates what you would see my rotating the holder about a vertical axis relative to incident light.
There appears to be a strong case for an over-date: 1786/5, but PCGS did not identify. The 1786/5 is a known over-date published by Droulers.
Pedigree: very old Spink paper envelope (approx 75mm x 75mm).