Acessories/Weapon Breakthrough/Evolve/Offering

[LuxiLuna]

I was wondering what the best weapons(colors such as green, blue and purple) to use as offering for the weapon I currently have and same with the accessories such as earrings, ring and necklace. I know that the one blue gem from the beginning of the game gave my weapon exp and only cost me like 1 copper. 

Would using green and blue offering weapons be the best to get it to breakthrough and evolve?

[Cuistre]

up to level 36 => purple

After lvl 36 => blue

[Emya]

In terms of weapon EXP:

Purple > Blue > Green > White

 

BUT at some point, using purple gears as feed material will cost more as they would require soulstones too so blue gears becomes a better choice cost-wise.