Obsidian

Arising in the wake of volcanic activity, obsidian is most commonly found buried at the base of long-dormant mountains. Although brittle, it naturally fractures into shear edges and smooth planes, a necessity for crafting knives and arrowheads in days long past.

Obsidian holds the appearance of a shard of glass, but with a natural shade ranging from deep purple to black. Smooth and reflective, obsidian will often display its contours with a glossy sheen.

• Coming into sharp contact with an Obsidian object may cause a creature to take 1d4 piercing or slashing damage. (This property does not allow obsidian armor to inflict return damage.)
• Weapons made of Obsidian that deal either piercing and slashing damage gain the positive benefits of both damage types, and only suffer downsides that affect both damage types.
• When a creature makes a grapple attempt against a creature wearing obsidian armor, it takes 1d4 slashing damage.