Diamonds is the premium currency of the game and is generally used to skip time requirements and speed up your progression. They can also be used to purchase shields and teleports and the rarer commodities that are required to complete some building projects.
Log On
If you log on daily and are part of an Alliance that has more than 50 active members you will be able to collect the attendance bonuses each day. Not only will doing this give you up to 25 free diamonds a day, it may also get you some resources and a few speed ups.
Purchases
Some resource offer packs will include free diamonds when you purchases them.
Daily Challenges & Clash of Zones
The Daily Challenges and the Clash of Zones daily tasks offer free diamonds if you complete them. They could be to train soldiers, finish buildings, or do research, or even a combination of those. Occassionally it will involve leaving your base and raiding the enemy. There are 3 levels of Daily Challenges and the first one will usually get you 100 diamonds amongst the rewards, The second level will get you between 400-600 diamonds and the third level offers a huge 2000 diamonds. To have any chance of completing a level 3 Daily Challenge you will need a bit of luck with timing and plenty of speed up items to get to the totals needed.
Create an IM30 Account
When you leave the game there will be a button that lets you to bind your IM30 account. If you create an account you will be able to recover your game progress if you change your phone or switch to a different device. You will also recieve 100 diamonds as a gift.