I got a few of these last year at our local auction... the males grew noticably larger than the females and the males also developed a nice hump on their head (nice for their smaller size at least).
Mine make great 'dithers' for my SA/CA Cichlids. They are also fairly eager to breed. They rarely breed as the smaller species in a community set up, but all I have to do is isolate any male and any female for two weeks and I have fry.
The Red Jewels and Blue Jewels are actually different speceies. Pet Store variety are often hybrids of the two. I'm not fluent enough with them to know if yours are true or hybrids.