This is the livery button of the Rev Thomas Miller DD of Cumnock, Scotland as recorded in the Lyon Register in 1814.
Arms: Sable a cross Moline Argent a chief of the last.
Crest: A dexter hand with the first and second fingers pointing upwards proper.
Motto: Spei bonae atque animi (Of good hope and courage).
Image courtesy of the vendor, hantsreg