I'm really new to elvenar and I found out that the diamond is very necessary for improving the city
I am with
@alainemk this is not true.
Diamonds will speed things up and make it easier but you dont need them.
@Dew Spinner gave you a comprehensive list of how to get diamonds in game. I am just adding information to that.
The Magic Academy(MA) that you build in your city has a mystical object in it(golden chest in a crystal ball). There is a chance to win 500 diamonds in every other chest. To open the chest you need to craft things in the MA.
To craft often you need to climb the spire as high as possible to win combining catalysts (CCs) and spell fragments.
You will also need to participate in tournaments in order to get relics that you can turn into CCs in the MA.
Your ability to earn diamonds in your city will be pretty limited until you get into chapter 3.
So, while you wait...go to YouTube and search "minmax gamer spire". Pick out the three videos that suit your chapter(early game) and playstyle(catering or fighting). That way when the spire opens to you, you will be ready.
The amount of diamonds you win in the spire itself is dependent upon how many fellowship (FS) rewards are unlocked. When you look at a FS overview you will see a blue banner that says Spire of Eternity Trophies.
Bronze means they unlocked the 50 diamond FS chest.
Silver means they unlocked the 50 diamond and the 75 diamond FS chests
Gold means they unlocked the 50, 75, and 150 diamond FS chests.
In order to get the FS diamonds you have to reach the FS chest and it resets every week.
There are also several chances to win diamond prizes in the spire.
Again, you dont need diamonds but they are very nice. Good luck!