Is this hombrew version of Glasssteel balanced?

I am not sure why the spell was not included in 5e. It’s mostly used for flavor and cool factor.

Glassteel

Artificer, Wizard, Bard (Forge Cleric?)

  • Transmutation
  • Level: 3
  • Casting time: 1 minute
  • Range: Touch
  • Components: Glass to be transmuted
  • Duration: 24 hours
  • Saving Throw: none

This spell gives a glass or crystal object the strength and durability of steel. The Glassteel also becomes roughly the same weight as an item made of regular steel, within a few ounces. The spell can transmute up to 5lb of glass or crystal.

At Higher Levels. Every 2 spell slots above 3rd lv, you can increase the amount of material transformed by 5lbs. 10lbs using a 5th lv slot, 15lbs using a 7th, and 20lbs using a 9th lv slot.
Using a 7th level slot or higher to cast the spell makes the duration permanent until dispelled.