Envyrald

The Envyrald is a pristine and beautifully cut emerald that has a gentle green glow about it. One is created involuntarily by Covetous whenever they are summoned from the Abyss to Aum. Where it appears is entirely random, it could be right beneath their feet or thousands of miles away. The gem itself grants no power to anybody save the Covetous themselves, but mortals admire them for their beauty and jewelry made with them is incredibly valuable. 
Anybody who gazes at an Envyrald will see their eyes vividly reflected within the stone and be filled with a powerful desire to have it through any means available. Even the most honest of men may resort to trickery, theft, or even murder to acquire an Envyrald that has "caught their eye". Covetous have a certain sense for any mortal that has one in their possession, whether on their person or safely stowed away in a vault, and once they have found one, they will stop at nothing to take it. Every Covetous desires to have their own Envyrald return to them above all else, and obtaining it greatly enhances their power, even more so for every mortal who has gazed upon its beauty and desires to have it. The second strongest desire of every Covetous is to steal the Envyralds of others. Having the others' Envyralds provides them with no power whatsoever, but they still want them regardless.