The Edinburgh Assay Office is the oldest existing consumer production body in Scotland, established in 1457.
The Castle mark, representing Edinburgh Castle with the three iconic towers, dates back to 1485. The introduction of the thistle mark sat alongside the castle to denote standard silver purity until 1975. Since the 2000s technology has moved on; digital assay submission systems are now in place.
You can guarantee that any silver piece with the Edinburgh mark is of high quality.