Hellstone

Hellstone is a type of material in the Hellstone Coast. It is unknown what happened there but it is speculated the condensed blood of powerful Fiends seeped into the marble turning it into black marble with red veins. It became really light (compared to normal marble) and could be made to fashion a wearable armor. While it is heavier than normal steel plate armor, it is still light enough to be worn. While those that wear these armors speak about strange voices they hear, the Hellstone is considered to greatly increase the survivability of the user and granting them powers. The only weapons made out of Hellstone would be hammers, as swords would shatter on impact.

Properties

Weapons made from Hellstone weight twice as much and gain a Strength 13 requirement. The user gains an advantage on Shove checks when attacking with the weapon. If a Hellstone hammer makes a critical hit, they gain additional 1d6 fire damage. Only hammer-like weapons can be made from Hellstone. Weapons made from Hellstone cost eight times the base price.
Armors made from Hellstone weight twice as much and gain a Strength 13 requirement, however, if they already have a Strength requirement, increase it by 2. The armor grants resistance to all non-magical damage. Also, whenever the wearer uses the Dodge action, he gains a +2 AC bonus while his Dodge action is in effect. Armor made from Hellstone cost eight times the base price.
Shields made from Hellstone weight twice as much and gain a Strength 13 requirement, however, if they already have a Strength requirement, increase it by 2. The shields grant the user advantage on all checks against making them prone or shoving them, be it magical or not. Shields made from Hellstone cost five times the base price.