The Surugat are small, dark purple shards of crystal that contain necrotic magic. No one knows where they came from or when they were discovered, it just seems like they have already had them. Each Surugat is a limited supply of this magic energy and so they are in high demand. The Upper Class hides the secret of their power and just tell the lower class that these shards are precious stones called Tanzanite.
At first the nobles paid highly for these gems, but as soon as they had gathered enough Surugat they enacted a swift social reform. With the power of these gems, the upper class oppressed the lower class and suppressed any rebellions with the powers the stones gave them.
In order for the Surugat to work, the gems much be attached onto gold so frequently they are set into gold rings, necklaces, and other jewelry. In order to activate the Surugat gold is not the only requirement. Fresh blood too must be rubbed on the stone.
Although the power in the gems grants long life, there are side-effects that come along with their use over extended periods. One becomes much colder, crueler, and the lines of right and wrong grow much thinner and harder to see. As a result most noble men are killed by others, frequently members of their own family. The power from these gems is an addiction stronger then any drug known to mankind,