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
	1/21,250,000	8 months (~245.9 days)	25,000,000

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, but they are less profitable than Trading.

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 Crystals, as people offer better exchange rates via Trading.

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