This unusual material is made from water under extremely high pressure, usually obtained from the Elemental Plane of Water but sometimes from the blackwater trenches far below the ocean’s surface. The water swirls and flows continuously, sandwiched between fields of magical force.
Half of the Armour Class bonus from armour and shields made from riverine is a deflection bonus (round down). For example, a suit of riverine chainmail would provide a +2 armour bonus and a +3 deflection bonus to AC. This substance is considered masterwork and can be enhanced magically as any other armour.
Riverine is sometimes also used to create walls and even containers. Being enclosed in magical force, it is immune to all damage and is unaffected by most spells. However, disintegrate immediately destroys an item made of riverine, as does a rod of cancellation, a sphere of annihilation or a Mordenkainen’s disjunction spell, causing the water to spill out in a sudden rush. Armour and shields made of riverine do not form a complete enclosure, so breath weapons and spells do still affect the wearer. However, walls of riverine block ethereal travel, breath weapons and spell effects, just as a wall of force does.
| Type of Riverine Item | Item Cost Modifier |
|---|---|
| Shield | +4,000 gp |
| Light Armour | +9,000 gp |
| Medium Armour | +16,000 gp |
| Heavy Armour | +25,000 gp |
| Other Items | +2,000 gp/lb. |
Source: Stormwrack (Page 128)