nice looking rug, looks like a slightly courser quality sarouk (guessing just about 81-100 kpsi) probably from the early 1940's. The only thing is if it's less than 100 kpsi, it's probably not a sarouk, but a close proximity city rug. I can't imagine it being too much older than this, and it's probably not much newer. Safe to say it's a semi antique. The only thing I would be concerned about are the yellowed areas on the fringe towards the right hand and left hand side in the full photograph, and towards the top of the image (appears to actually be the bottom of the rug) there's one in the center. These areas could be dried out, although it's not uncommon for slight staining or oxidation over the years... it's just not consistent which leads me to believe dryness if that's a word
As for value, if the wear is very even, and the rug has no significant problems: if this were to get sold on eBay nr, I could see it getting every bit of $1000 after being cleaned I believe. It's tough to say though without seeing the rug up close and personal as you know. A lot of things that would give a rug strikes against it can't be seen from some of these photographs although the pile does look decent.
Mosaic you bring very interesting rugs to this forum, tell us a little about this one
