Might add that while it's a less common fineness, Iranian .900 silver is also usually marked as '90', though not often in European-style numbers. The '84%' mark shown below is from Rezazadeh's 'Collectible Silver Jewelry' (2001), the maker's mark described as belonging to the 'Ardokhanian' family, silversmiths dating back to the 19th century, with a workshop in Tehran since at least the 1930s.
~Cheryl

