Tolkien simply collected the parts for his mythos from those around Europe. Afaik, most of his creatures and races can be traced into some old stories. And every nation has their ghosts, pixies, gnomes and elves. I believe the names (troll, fairy, gnome) are quite often just different names to same \'creatures\'. But the creatures might be different by culture.
But back to the topic:
The list seems odd. You would place pewter above steel and Iron? I\'d change the list this way: [from strongest to weakest, respectably]
Mithril - Steel - Iron - Bronze - Silver - Brass - Pewter (tin?)
Though we could add some materials like wood and cloth (in different forms), and bone of course. I could imagine that cloth isn\'t suitable for weapons, but it can be made into an armour.
---
But there are some points I could take up. Now let\'s see, if steel has been invented, there would not be many reasons to use any other materials, except special properties and price. For cheap armour/weapon, use Iron which is very prone to rust. For special and magical properties, use silver (let\'s be Tolkienish and keep Mithril as a form of silver). Now a weapon made completely out of silver wouldn\'t be good, since silver is such a soft material (silver dagger against a steel plate?). So let\'s use \'silvered\' weapon instead. A blade which has silver veins added on it, to deliver the desired effect (kill \'em werewolves!).
For armour, I don\'t quite have a point why to use silver, unless it also has defensive magical properties.
>>>end_of_rant
