☀https://imgur.com/a/Qdb6R3NThey are high yielding as a blessing, but their primary usage is to create Temples, which permanently lower the amount of Blessings requires to fulfill the Gods' demands and contributes the Holy Man and Halo masks.
Because of the diamond's incredibly high rarity, it is advisable to have someone equipped with a Miner's Hat mine all boulders made available to the commune to maximize the chances of acquisition.
Diamonds are not only obtainable from Giftboxes, but they are more likely to be acquired from them than to be mined from a boulder. This makes farming the Giant Chicken a great method to obtaining diamonds.
If you can work together with a player with a Crown and have a large amount of any kind of seed, the player with the crown can reset, be revived by you or someone else, causing them to spawn with a diamond. This can be done repeatedly for an absurd number of diamonds.