Mask of the Deceiver

 [Queen Azshara's Dressing Gown] does not require 450: I had about 300 when I got it. Additionally, assuming "You will not usually find a second copy of a common object until you have found all the artifacts of that race." is true, then a few other night elf items; indeed, I got offered twice in a row a common artifact I had already found while sitting at 410 and 415 respectively (after that I waited to reach 450 to solve more), and I had yet to find the  [Highborne Soul Mirror] and the  [Kaldorei Wind Chimes].

However, while sitting at 500 and having yet to find  [Zin'rokh, Destroyer of Worlds] I got offered a common artifact I had already solved, so I'd venture the statement above is wrong, or incomplete (it seems indeed you won't be offered a second time a common artifact as long as you have some to discover, but you might be even if there's some rares you didn't discover yet). On a side note, once you've discovered all common artifacts for a race, the game won't wait for you to have discovered them all 2 times before offering you one for the 3rd (or more) time. Gorkk (talk) 03:16, 3 January 2011 (UTC)

From my experience, I can confirm that the "You will not usually find a second copy of a common object until you have found all the artifacts of that race." is indeed incomplete. For example, I have been at 525 for some time, and while working on the Nerubian artifacts, I got no repeats of common items until I had found all the common Nerbuian items, and from that point I got repeats of commons items until the game gave me  [Blessing of the Old God]. I'd suggest something like, "You will not usually find a second copy of a common artifact until you have found all the common artifacts of that race. Rare artifacts never repeat (you can only ever find a rare artifact once), and you are not guaranteed to have found all, or indeed any, rare artifacts of a race before finding all the common artifacts of that race." Nasrana (talk) 13:03, 9 January 2011 (UTC)