It's hard to use this card because you have to forgo other valuable accessories, and pay a big upfront cost with a delayed reward. But once it is in play, it will likely trigger many times. The chance is almost 1/3 for every skill test in many scenarios. Like Jim's Trumpet, it is better in multi-player because it includes your teammates token draws. In this setting it will likely trigger almost every turn. Every time it triggers, you get +1 or +2 net effect. If you always take the resources, it will repay itself after it is activated 3 times and then start generating profit. This works better if your deck can deal with the upfront cost and want money to pay for pump assets like Physical Training. The other strength is the flexibility to give you what you need.

If you do choose to play with this, it makes Olive McBride and Dark Prophecy better.

I don't really know what to think about this Relic...

Jewel of Aureolus costs 3, which is huge in a mystic deck. And guess what ? At 3 XP, it can only be played by wizards. Huge cost indeed, but for what results ? "Draw a card" or "gain 2 resources" every 1 or 2 turns. It has to trigger 3 times to refund itself (1 card, 4 resources) and 3 times to generate as much value as Emergency Cache. Unless you're playing with many players, it means often 6 turns at least. After that, it's bonuses ! So, it nets a value only if it's played during the early game.

Tell me if I'm wrong, but, playing as Agnes Baker, I often want to play staying power during my first turn. That means, Shrivelling (lvl0, 4 or 5), Rite of Seeking (lvl0 or 4), Peter Sylvestre (lvl0 or 3). And cards to support those assets, Spirit Athame, Holy Rosary... So, Jewel of Aureolus often comes on the board after spells, and doesn't directly empowers it. So, it nets a bonus, yes, but a very thin one.

It's even worse when you draw it during the scenario. It's close to impossible to extract value from it. Hopefully, it has a Wild Icon, so it's not a totally dead card.

All in all, it's more a less a filler, not a premium card you need to get. What's more, mystics have a long list of XP-intensive, must-have, cards. (Shrivelling, Rite of Seeking, Grotesque Statue...) When it will be time to invest in resource-gathering, Emergency Cache (and the upcoming Emergency Cache) might outshine Jewel of Aureolus - at a lesser cost.

TBH I'm just getting into Mystics, they always seemed expensive and tricky for my small mind, but this seems like a natural with Jacqueline Fine, even if you're running a Relic Hunter to add this on to a Will boost accessory like Holy Rosary or Crystal Pendulum. Set Jacqui up with herself, her signature, and Olive McBride - not to mention other event cards like Dark Prophecy - and this seems like you'd be swimming in cash and draw for the majority of the game.