Unlike Alchemy, rare recipes are essential to make a lot of money out of Jewelcrafting. Nevertheless, some decent gold can be made with this profession. I find the best way to make money with it without rare recipes is to farm (or buy) Adamantite or Fel iron to prospect. Basically what you do it prospect all the ore you have, open up your Jewelcrafting profession window and make sure the “Have materials” box is checked. Now head over to the Auction House and check which gem cuts have either the largest profit (on a few servers, some cuts still go for 5-10g) or ones that there are few/none in the AH beforehand. Then go and make 5 of each jewel (the jewels depend on the option you chose above), until you’ve got no more gems.
If you can’t find any good profit opportunities, just list the gems at the normal market price or if you’re really rich, buyout all of them under a certain price and relist them at a higher price. This method is quite common practice in a few servers and you can literally control entire gem markets if you’re that rich.
Important note: NEVER prospect for anyone else regardless if they’re paying you as the gems will be used to undercut your auctions that you list and it only takes a few of these guys to ultimately bring down the whole market by a few gold thus bringing down your profits as well.