Mondorium

A rare and dangerous metal. It's radiation prevents magic to take proper form. Weak magic will fall apart and become nullified, while stronger magic will be either weakened or spiral out of control. It influences the development of magical effects and prevents magic from passing through it, but already stable effects should remain undisturbed.

Religious significance
follows

Effects on spellcasting
Direct contact with large amounts of Mondorium, like wearing armor or multiple shackles infused with it, will suppress the ability to use (most) magic. Overcoming this effect requires a DC 20 Con Save. If the Save is failed, the spellslot will remain unused but the caster will take 3d6 force damage in retribution. In case of success, the spell is cast normally with an additionally triggered wild magic surge, but the spellslot used must be one level higher than usually required. Moreover, magical healing is weakened and the amount of HP won through magic will be halved.

Mondorium Armor
Armor made out of Mondorium has slightly worse protective properties compared to steel and brings the drawbacks mentioned above with it. However, it grants it's wearer advantage to Saves against magic and resistance to force damage.

Mondorium Shields
Shields made out of Mondorium bring the drawbacks mentioned above with them. However, they give a bonus to Saves against magic equal to their AC, and spell attacks against the holder have disadvantage.

Mondorium Weapons and Ammunition
Weapons made out of Mondorium bring the drawbacks mentioned above with them. However, if an attack with such a weapon/ammunition forces someone to make a concentration check to uphold magic, the check is made with disadvantage.

Mondorium Bombs
These explosives contain Mondorium powder and cause no direct harm. As an action, the bomb can be thrown up to 60 ft. No magic can be used inside of a 10 ft radius from it's impact for 1d4 rounds unless the caster succeeds a DC 20 Con Save. If a creature moved outside of the impact zone but was caught in the blast, it must succeed a DC 15 Con Save or will be unable to use magic for one round. On a successful Save, the spell is cast normally with an additional wild magic surge.