You can't get it in the mission. You can get it by going to the mall to buy it with coupons or making a wish in the wishing pool. There may be some in the trading place, but you may need gold coins or coupons. It will be worth it here

If you level up here for every level from 1 to 15, you will get 2 iron diamonds in 1 level.

And teach you how to dig and inlay, the steps are as follows:< /p>

First click on the synthesis house. There are many options in the synthesis house. You click on the "Weapon Excavation and Inlay" option, then click on the weapon excavation where you want to inlay gems. Then inlay will appear. Just click on it< /p>