Dutch(?) windmill hallmark and purity

[jayvee2]

Hello!
I am new to this site so if I need to ask this elsewhere, please let me know.
I purchased this match box cover which I believe to be silver or silver plate. It is marked with what appears to be a small Dutch windmill followed by a small NIO then a larger number 90. Is it Dutch? does 90 mean 90 percent silver? Any help is appreciated! Thanks!!!

http://sv1.letmehost.com/sv1/16/hallmark_close_3.jpg

http://sv1.letmehost.com/sv1/16/new_cover.JPG

[admin]

It is silverplate, were it silver the marks would be found here ->
Dutch Hallmarks