I've been trying to be too clever. I think it's time for something... simple. Something obvious. Something an apprentice would think of when asked to make an enchantment. Something like a sweet magic sword.
Consummate Sword of Fire
Creo Ignem (Rego) 15 (Base 5, R: Personal, D: Diameter, T: Individual, +1 Rego modifier, +-0 Once per day)
An iron longsword with a soft leather wrap over the hilt, and a pommel of basalt imported from the Mediterranean. The blade has a single chopping edge, more common in barrow artifacts than modern weapons. When the bearer recites the first line of the Lord's Prayer, the blade is wreathed in fire for one diameter. This flame doubles the weapon damage score for the blade (or adds +5, whichever is greater), and can start fires as well. The Rego requisite prevents the flames from damaging either the sword or the bearer's hand. The lab text for this item includes the material bonus for basalt's Ignem sympathy.
The Consummate Sword of Fire was smithed at a covenant deep in the Rhine. When the covenant drove the local highway robbers out of the area, continued rumors of banditry attracted faeries who took on the same role. A clever Merinita spread stories of monsters who were afraid of bright light, and the faeries were honor-bound to follow the rule. Of course, a flaming sword will dissuade human robbers as well.
Gladius Plus Ultra
Rego Terram 15 (Base 3, +2 metal manipulation, R: Personal, D: Concentration [+5 holds concentration], T: Individual)
A bronze shortsword, simple and solid in construction, with a hilt wrapped in gold wire. The name Gladius Plus Ultra is engraved along the flat of the blade. The enchantment on this sword causes it to repair itself to the best of its ability whenever it is damaged; it reshapes itself when bent or dented, and sheds rust the moment it forms. The Gladius appears largely the same as it was when first forged, with only a small amount of bronze worn away like a bar of soap. The lab text for this item is either lost or buried in a library somewhere.
This sword was a product of House Verditus' third generation of apprentices, in a more innocent time when an "indestructible sword" was a novel idea. The Houses' early internal vendettas eventually saw this sword fall into the Mediterranean Sea, where it rested under the seafloor until it was dredged up recently. The value of this centuries-old artifact is mostly sentimental.