I spent more time on this yesterday as well.
Preliminary findings;
-The ring was made by John Miers of London, "No. 111, Strand, opposite Exeter Change." Miers lived between 1758 and 1821.
-The setting is Heliotrope, commonly known as Bloodstone. It's been used since ancient times, and has a variety of talismanic beliefs associated.
-John Miers is a name well known to history; 10 specimens of his work reside at the National Portrait Gallery in London. There are probably hundreds of surviving works in private collections and museums around the world.
-The Scottish Poet Robert Burns refers to Miers' shop by name in a letter to his wife. A jeweller for respectable people then; and best known for his work in miniatures.
-Samj and I had similar thoughts...perhaps we shouldn't assume that William Bligh was an Epicurean any more than we should assume that George Suttor was. Perhaps the ring was gifted to him.
Anyway, I'll have more later.