Tier 3:
Golden Vambrace + Cloth Armor + Null-magic Mantle ---> Gauntlet of Riches ( +40ar +30mr)
Quest Reward: Unique Passive - Provides Aura that gives nearby allied champions 10% of your BONUS ar/mr
[Passives/Actives]
Unique Passive: Midas Touch - Healing or Shielding an ally grants you both [5/10/20] gold [Tier 1/2/3]
Active: Target Ally and yourself both gain +15% of your total ar/mr for 5 seconds (75s cooldown)
ALT:
Golden Vambrace + Sightstone ---> Eye of Avarice (+25 ar, +200 hp)
[Same Quest, same passive, Sightstone active]
So I gather that you intended this to primarily be a support tank item, like Thresh, Alistar, or any tank/supp with cc for Stoneborn [Ornn?].
Assuming that, I tried to balance this for that purpose. In theory, this should never be broken, except maybe on Sejuani? Which is a possibility but even with that, she probably won't be too bad. Assuming ~400 armor, 320 mr [60? base each] with her passive, quest effect would only be 34 armor, 26 mr. Using the active would grant 60/48 respectively, so that's a total of 94/74 for only 5 seconds, which is significant but not bullshit. I'm not sure if the active is really strong enough, too strong, or what, so that could probably(?) use adjustments. Feedback is appreciated ofc.
[[Edit: Fixed math, calculated active at 10% not 15%]]