Most statistics should be self explanitory.
Rarity: The relative rarity of the item. Somewhat misleading, due to various mechanisms of artifact placement, but it gives you a decent idea of how common the item is. If it's set to False, this can't appear randomly, only through special events.
Level Range: The range of levels this can appear for. I believe this checks the level of the enemy it spawns on.
Material Rank: The equivalent material level it is. Combined with the level range, these two factors usually determine what dungeon a given artifact can spawn in.
Damage Modifier: 1=100%. This is left like this in order to simplify the already huge workload of reformatting the artifacts, as this is how it looks internally. Note that Strength modifiers, when existant, count downwards from 100%, rather than upwards towards it. So -0.5 Strength is actually a 50% Strength modifier.
Status Resistances: 1=100%. See above.
Speeds: 1=100%. See above.
Healing Modifier: 1=100%. See above.
As a note: This was taken from the SVN. As such, it might actually be a little too ahead of date, and a few details may be off from 1.00 final. The only major differences are the set combo for Unsetting Sun/Dawn's Blade, and the Antimagic Wielder bonus for Blightstopper.
> World Artifacts
> World Artifacts Part 2
> Far East World Artifacts
> Boss Artifacts
> Zone Artifacts
> Assorted Artifacts