I am a huge fan of crafting items from exotic materials like starmetals or naturally occurring alloys with properties that can't be replicated by mortals, but when I try to come up with something, I either reach way too far, or just fall flat.
The last time I tried was something called inksteel. It had some property that gave weapons made from it some bonuses to being hidden and sneak attack (this was before we knew SA applied to all attacks made under the correct conditions). Armor gave stealth bonuses.
What kind of special materials have you all introduced to your players?
I made these up for my E6 game.
Work Hardened Bronze and Iron Weapons
The hardness of these weapons is reduced to 8.
Proper steel weapons, quench hardened and tempered, have a hardness of 10.
Fine Steel Weapon
Pattern welded steel, produced in the most technologically advanced societies, has a hardness of 12 and grants a +2 bonus to damage on sundering attempts.
Low and high carbon steel can be combined to create weapons with great durability and sharpness. Often single edged, these weapons can only parry safely by using the sides or back of the blade, keeping the striking surface sharp.
Add +1 Damage. Hardness 12 in hands of proficient user. Gains the broken condition permanently when struck against fine or combination steel another by an untrained warrior.
These light weight swords are known for speed, though they lack the ability to withstand heavy impact. Add +2 to Initiative. Hardness 8. Reduce weight by half.
Mage Bane ~ Rare plant that a trained alchemist ( NPC Class before the PF Alchemist Core Class) could work into a non lethal poison that temporarily inhibits spell casting. Very illegal in several Wizard heavy kingdoms!
Very expensive and profitable if you wanted to take the risk smuggling it across borders! Made for some great runs when the PC figured out the Caravan they were guarding was packing some of this stuff!
Lots of little things just to add some spice to the game and not really change anything in the mechanics.
Have Fun Out There!!
~ W ~
I've never made my own metal, but I did bring a 2nd edition metal back to life in my game:
Baatorian Green Steel, I never liked the 3.0 version so I did my own conversion loosely based on the original 2nd ed version:
For piercing and slashing weapons only increase damage to next higher damage die, the weight of metal weapons is halved.
The fluff for the metal said it was half the weight of normal steal, but could hold a really sharp edge.
For armor half the weight and reduce the armor check by 3. Count is as one category lighter then normal, example: Medium armor counts as light.
If you have ever played 2nd Edition D&D Planescape, this is more closely how the metal was treated.