A special kind of slaves known as Al-Jinks are very similar to regular slaves but considered more as a decorative material than workers. The most expensive material in the world, more expensive than even diamonds. Like cut diamonds, Al-Jinks are only measured in whole pieces and their quality is usually measured in the amount of years invested in their training.
Like other materials, they are sometimes used in alchemy when a special "flexible ingredient" is required. Much more often, they become mere decorations in the houses of the wealthy.
Much like the way to refine a raw diamond is cutting, and a way to refine gold ore is melting, a way to refine a regular slave into an Al-Jink is stretching. Flexibility of an Al-Jink is the universal measure of quality and it can be always improved over time, although without proper handling it may also very quickly degrade.
Some of the world's most refined pieces are normally to be found in royal chambers and gardens, while less refined pieces are sold back and forth in the market. The more flexible Al-Jink becomes the higher is the price, so the very same Al-Jink can gradually progress from a regular cheap slave to one of the most expensive pieces in the world.
Many people believe that each jewel has its own character and personality. Well, Al-Jinks do have their own personality as well, usually the more refined Al-Jinks have a very calm, content and very obedient nature. The cheaper ones can be a bit rough at times. Of course, properly handling an Al-Jink requires a skill, much like any other material it's very easily broken in wrong hands. Al-Jinks of hte highest quality can only be handled by the world's best stretching masters.
When sold in the market, they're strictly bound or even chained to the merchant because one well-raised Al-Jink can be worth a large bag of gold and thieves are never sleeping.