The problem with Riverine is it is very, very, very obvious to use Disintegrate on it!
As best as I can tell, the material 'glassteel', most recently from Champions of Valor, is one of the best structural / durable materials in the system. Remember, Crystal and glass based things can be Shattered. Metal based things, which can be Rusted, Melt Metalled, Shape Metalled, Repel Metalled, Cool Metalled, or Heat Metalled. Wood based things can be Repel Wooded, Warp Wooded, Wood Rotted, or Wood Shaped. Stone based things can be Stone Shaped, Stone Shattered, Stone to Fleshed, or Transmute Stone to Sanded. Animal based things (Flesh, Chitin, Leather) can be Flesh to Iced, Flesh to Salted, or Flesh to Stoned. Wall of Force based things (like Riverine from Stormwrack) can be immediately annihilated via Disintegrate. So as best I can tell, Glassteel is something that kind of fits in between things, where none of these work. and with the weight of Mithral, the Durability of Adamantine, and the friction of Glass, it's great for making EXTREMELY valuable gear.