Include gems in crafting. The gem would directly contribute by adding an additional Mod and would be influenced by the color. The actual size of the mod would be influenced by the quality of the gem.
For example, I want to craft a 6 property weapon and really have a surpplus in gold. Let's say I'm sitting on 60-70 million. I am searching for that nice 2h weapon upgrade and I have an opportunity to attempt to forge 4-5 6 property 2h Bows. Well, let's say I want to burn a Ruby Star with each attempt, which has an inherent cost, and the Ruby Star would guarentee a bump in the sheet damage of the crafted bow based on a percentage range attached to the quality of the gem. In this case, 20-30% increase in damage.
The kicker is coding in a type of ceiling on the benefit. If you rolled a perfect 2h bow then you can't have the gem contributing on top of the perfect roll to create a truly unique beyond godly item. That is the only constraint.
This would be a excellent idea for a gold sink versus increasing repair costs, plus for many of us that do not see Crafting as a viable option b/c we've put 10-20 million into it just to play around... This would fix crafting.
You would need to debate the possible outcomes for each gem but I roughly like the below:
Ruby - Chance for increased sheet damage or +str
Emerald - Chance for increased crit dmg or +dex
Topaz - Chance for increased Elemental Damage Random Type or +int
Amethyst - Chance for increased Life on Hit or +vit
Please add to the OP if you find it has merit! Thanks!