Saying, that you want a jewel cichlid is like saying you want a convict cichlid. There are many kinds, with very different attitudes, water requirements, and sizes....it's not a specific enough question. There are also a lot of hybrids and line bred strains out there too. Do some research on what kind you might want. If you are looking for a red, pretty fish with an attitude then you might do well with Hemichromis guttatus or H. lifalili. Both are fairly medium-level on the snarkiness....lots of sass, but if stocked correctly it won't be a total bloodbath. Beware H bimaculatus. Depending on who you ask, all -or nearly all- in the US are not really bimaculatus (they're usually lifalili, guttatus, or a hybrid). Any of the green/turquoise varieties are hybrids or line bread from what I've read. Very pretty and nice if you want to keep that color, but they don't represent anything wild. I'm currently working with H sp. "guinea 2", H cerasogaster and H stellifer. The Guinea 2 are really shy but murder anything I put in their tank that's not one of them. The cerasogaster and stellifer are awesome but further up there on the "angry cichlid" scale than the others. The Guinea 2 and cerastogaster are supposed to like their water a bit on the soft side. Guttatus and lifalili will breed like rabbits even in hard water.
Then there are the 5-spot jewel cichlids (H elongatus, H fasciatus) which I think are still in the Hemichromis genus but there's some work going on right now to reassign them to their own genus. They're a whole different bag of angry. You need a big tank and a plan to manage aggression. They're not really what I'd consider a "jewel" cichlid anyhow. They're just so different in many ways.
Just keep in mind that the jewels will hybridize with each other at the drop of a hat and are often passed around with the wrong ID, so if you want to keep a specific kind, be picky about where you get them from. They're IMO one of the most often mis-labeled cichlids out there.