Gems

Gems can be found with the Gem Finder, which is bought in the shop for 1,000 after crafting a Community Center 1. There are 5 types of gems: Sapphire, Emerald, Ruby, Diamond and Blood Diamond.

There is also Blood Crystals, which are used as in-game currency and can be purchased for real money or found after obtaining tier 2 research in mining.

Gems

Gem Type	Rarity	Average Time per Gem	Value
	1/100,000	About a day (~28 hours)	100,000
	1/300,000	Half a week (~3.5 days)	200,000
	1/500,000	Almost a week (~6 days)	500,000
	1/500,000 + Tier 2 Research in Mining Drops multiple, around 100 pcs	Almost a week (~6 days)	Cannot be sold to NPC shop.
	1/1,000,000	One and a half weeks (~11.5 days)	1,000,000
	1/25,000,000	Three seasons (~289 days)	25,000,000 (never sell this)

Note: Selling gems is not recommended. Instead you can trade them with other players or at the Gem Goblin Shop.

Uses (non-BC)

Gems are used for...

• Upgrading Tools (and Berserker Amulets/Rings), improving their speed and/or efficiency. You need to socket the gems in order by rarity: Empty -> Sapphire -> Emerald -> Ruby -> Diamond -> Blood Diamond.

• Crafting keys, which are used to open Treasure Chests. The better the key, the more chest slots you have. More chest slots means a higher chance if getting better loot. (see the page on treasure chests for more info)
• Upgrading Rings

• Gem Displays , which are useful for Crafting XP and can be sold for some coins.

Also:

If you have T5 Mining Research, you can convert 10 of one gem to 1 gem of the next rarity. This is usually used to create Blood Diamond.

Blood Crystals are different from other gems, as they are used as a form of currency.