Most jewel djinn are born underground in mineral deposits, most spectacularly geodes, and there they live quietly in groups, chattering and singing sociably, sharing stories the water and salts in the aquifer told them in their travels through the geologic formations. There are other djinn such as those who reside in pearls in oysters and learn from octopuses, or in oozy amber sap where they learn from trees and trapped insects. When the gems are discovered and mined, however, they become aware of humans. When the miners sell their goods to the market, the djinn enslave the humans they call bearers, and take on the role of teacher, parent, and master. Humans prefer the word "enthrall" to explain their attraction to gems.
A single djinni protects and controls its bearers by a force that is undefinable in the language of The Encyclopedia of Minor Deities. They constantly take the moral temperature of their bearers and give pain to the evildoer, subtly change the course or pathway of the misled, and send the righteous on sunlit roads safe from bandits. Djinn love to have their stones polished and newly faceted at regular intervals, and they reward their bearers for such practices by shining brightly, allowing them to attract others. The bearers are, of course, largely unaware of the changes in their lives, convinced the path they lead is controlled by personal allegiance to their primary gods.
If a bearer amasses a large collection of different gems, the new collective of djinn will learn from one another and then try different strategies to control their bearers more sneakily, to widen their own experiences. In attempts to gain new humans to examine and play with, the djinn may cause an adult bearer to develop grandiose ideas about running for political office or overrunning a new country, or becoming a writer, all of which involve, the djinn believe, the greed for more and more jewels. The djinn love intrigue, and an adult might be cozened into cheating on or murdering his or her spouse, and or his or children children to run off and take up odd behaviors or marry in oddly appropriate patterns.
The djinn of jewel collections that are broken apart and sold to different collectors go on to subvert a new set of humans. If sold as a group, the gems may end up in a museum, where the djinn can amuse themselves by attracting museum-goers and encouraging them to begin their own collection strategies. Another outcome perpetrated by the hapless and harried bearer is to simply bury the collection in a "hoard," where the jewel djinn can speak to the topsoil and attempt to understand burrowing insects. In these cases, the djinn have been known to chorus loudly enough to be heard, become discovered, and go on to greater human manipulations.
Note: Entries in The Encyclopedia of Minor Deities are entirely fiction of the magical realism variety.