Unfortunately I can't see the marks, (close-ups are needed to research further) however the "Lion Rampant" on the front of the ring, is the Royal Standard of Scotland. Also known as the Banner of the King of Scots, it is one of Scotland's most recognizable symbols.
Although now officially restricted to use by representatives of the Sovereign and at royal residences.
An earlier recorded Scottish royal standard featured a Dragon, which was used at the Battle of the Standard in 1138 by David I (1124?1153). Reference:Strong, John; Tatlock, Perry (1950). The legendary history of Britain: Geoffrey of Monmouth's Historia Regum Britanniae and its early vernacular versions. University of California Press. p. 329.
