Starfall Ore
This burnt red ore is hard to extract and even harder to work with however it can produce fine weapons and armour. Items forged from Starfall have a dull red look to them but when active glow with a red light. The greatest advantage to Starfall items is that it does not interfere with low level, 3rd or less, arcane spells. In theory a wizard could be clad in Starfall armour and still cast spells with no hindrance. In practice the rarity of the metal would make this very unusual.
The other, alleged, drawback is that over time it interferes with the mental state of wielders and owners. This is strongly disputed by the Starfall Smiths but the rumour is that over time it brings out the worst in people. Generally the ownership of one item is considered harmless but as more are accumulated there is a tendency for the owners to turn more malicious and unpredictable.
The Starfall Smiths are themselves renowned for their fickle natures but are masters of their arduous craft. They serve long apprenticeships and only when masters with mundane metals are they allowed near the beloved Starfall Ore. Even then the life of a full Master Smith is short with few lasting longer than 10 years after attaining the position. Rumours talk of them being driven insane or thoroughly evil, that the Smiths eventually take them away to places unknown of.
In Game Terms
Starfall items can be up to +3 in strength: depending on the purity of the item. A sword or shield would glow dark red in combat but would otherwise appear to be a dull reddish metal. The items are magical and would appear so if detected for.
After a year of carrying more than two items, or a full suit of armour, then an individual most make a Will Save (DC:15) or have her or his alignment take a step towards chaotic evil. Time is cumulative, so if you abandon your items for a month when you return your previous exposure still counts.
A sword, shield or general weapon will count as one item while a full suit of armour would count as two.