Nice pin. The figure on top looks like the standard Scottish Lion Rampant to my eyes although the mane is a bit subdued. The stone is hard to identify from your photo since the way it displays could have a lot to do with lighting. In order to find the age, you'd have to investigate the maker's stamp on the back if there is any. That would be the best place to glean clues. Just looking at it I would say it's not older than Victorian, but it could be a very recent production as well.