Great amount of crit and fire res is a nice bonus. Strength is a touch low but still decent. I can offer 5 Mil but you might be able to sell it for double figures on the AH.(bigbad#2504 add me if you're interested)
My guess around 10 mil maybe more, if it had as or crit dmg then it be worth 20+ easy. I've sold maybe 20 amulets and prices you see on the auction aren't usually a good indicator of sell price. Especially if there isn't many similar and the ones listed have astronomical prices. Example, had a really nice pair of depth diggers drop last week, checked the auction and the nearest pair were 21 mil, undercut that price and listed mine at 17, didn't sell. Relisted at 12, didn't sell even tho every other pair with 160+ vit and 160+ dex are 10 mil higher.
In these kinda cases I usually list it at a low min bid, like 5 mil and put the Bo close to what similar items are listed at so say 15-20 mil. If its really worth the Bo someone will buy it, if not it should get at least bids.