Jewel refuses to give up any actual information about his past or his family. Rather than brood about it, though, he seems to not think any of it important.
Manik and Gear first met Jewel during a run-in over a Chaos Emerald. Rather than fight over it, they decided to challenge each other for it, as each person had their own emerald to wager. However, the contest was cut short by the untimely arrival of Metal Sonic. They decided to join forces in order to defeat Metal Sonic, and have since then been working together to gether the Chaos Emeralds.
Jewel is telekinetic, an ability he focuses through the jewels adorning his outfit, which glow when he uses them. He uses his telekinesis most often for flight and firing waves of energy as an attack. He's stated that telekinesis in his species, whatever that is, is just as rare as it is in mobians. He's also very acrobatic, and does not require his telekinesis to be so.
Jewel can only use his telekinesis when he is able to calm the storm of his mind. While he is normally calm and collected, he can be pushed over the edge, at which point his telekinesis shuts down, and he is rendered a normal... whatever he is.
Jewel is often jovial, as much a clown as he is an acrobat, and willing to do many things for a joke. However, he refuses to take part in anything that may demean the recipient. He's also very slow to anger, often calming Manik down, and slow to tears, always taking everything in stride. He often considers the past something to learn from, but not something to dwell on, a point he often repeats when refusing to speak of his past.