Allods Online Forum

I'm not sure at 100% but should work like this:
rare astral gear has a 3rd stat in them that can be changed.
For example a wand can have:
2 main stats (vigor + stamina)
2 secondary stats (proficiency + vitality for example)
1 additional stat with a low value (like anger)

This last one can be changed using an Insignia.
You can use Rare Insignia on Rare items, Epic Insignia on Epic...and so on. Obviously you can't use Rare on Epic.

You can use them only on astral gear and not on lower level gear like crafted or reputation.

I'm not sure if you can change an offensive stat like Anger in a defensive like Willpower.

Tested today.
After you upgrade your lv60 item from Uncommon to Rare (for rare insignias) it receives one additional stat. For example: my Wand of Profficiency gained +0,71 Anger. And it is this stat that can be changed with Insignias.
There is no limit as to how many times you can change this stat.

The only limitation is that the items that have bigger bonus for offensive stat (for example Wands) receive additional offensive stat (Anger on Wand of Profficiency) while items with bigger bonus for defensive stat (for example Rings) receive additional defensive stat (Bloodlust on Ring of Vitality).

Quoted from "mikha"

I'm not sure if you can change an offensive stat like Anger in a defensive like Willpower.

Nah, you can only change offensive stat into another offensive one.

Good to know thank u R2