Those "persian saddle flasks" are somewhere between 1 and 1000 years old, probably closer to 1[]. I see them in antique stores for $10-40. I dont know the story behind them but if I had to guess I'd say people brought them back as souveniers of thier trips to the middle east.
MATT is correct. I've seen quite a few on Ebay...even bid on some and got beat down. They usually go for more than $45.00
There's also a more recently made one (repRo)...looks a bit more crude.
JAGEE...all of them I've seen are heavily pontiled. And I believe there are indeed authentic ones well over 100 years old. First one I ever lusted after was seen by me at a show in the early 1970s. Too much money then though...as now...[]
if it has good ware on it then it is worth about 150 in that color. Most are tealish. An emerald one like that would a little less common and worth more. But like it has been said they range from 1 - 1000 years probably and the method of making them has not changed the slightest bit...
That ones a Naval Boarding Weapon. This is the real flask.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=160155656727&ssPageName=STRK:MEWA:IT&ih=006