Lightrand

Steef's signature Blade.
Also named Lichtrand or Light's Edge.

The Lightrand is a sword made of Solarstone, a gold colored material that's able to absorb high amounts of sunlight in a cubic centimeter.
When used in combat, if the Solarstone gets damaged by scratches, it'll unleash the sunlight it stored in it. causing an explosion burst of light.

While that's just a scientific effect, it has been considered sacred as the years passed. And rumors sprout that the sword has been blessed.
Some rumors included that the blade could be a combination of the four elements that hides in its gems, the actual reason why the gems are there is unknown though.
The source of the raw Solarstone is however lost, That's because it looks like a plain rock if it no longer contains sunlight. So it couldn't be researched anymore.

Steef discovered that the Solarstone in the Lightrand is able to conduct heat and flames, causing the blade to be heaten up, making it glow.
In combination with Steef's firepower, it's also able to flare a "fire of light". giving the flames a golden color.
If it cools down after heaten up, it'll cause it to temper itself. recovering itself from the scratches it caused. Effectively causing it to last almost forever.

Despite it's not been an actual 'holy' weapon, It'll still show's it's effectiveness against dark creatures.