Gems/Spinel

Spinel is a medium sized dual-purpose utility Gem. One purpose is to be a decoy/lure for hostile entities, meaning that Spinel draws in mobs. The "drawing attention" effect lasts for a small bit, with a relatively wide radius so that Spinel can draw in the hostile entity or entities from far away.

Her other purpose is to reduce the chance of a gem rebelling, making her most useful around Kindergartens and newly emerging gems. If you rejuvenate a gem near a Spinel and resummon the rejuvenated gem, she will also reduce the chance of them rebelling again.