Bloonstones () are a type of currency in Bloons Monkey City and its mobile counterpoint. Their appearance is of a blue gem shard and are obtained through multiple ways, including completing a tile with no lives lost (rewards 5, 10 in Hardcore Mode, or 2 on mobile), leveling up (rewards 20 on flash or 4 on mobile), winning a Volcano Terrain tile, a cave tile, and certain Special Missions, or by watching some videos (earns a varying amount of Bloonstones, not available to everyone). On mobile, sending the first MvM attack will give 5 each GMT day and 2 after that attack. They can also be earned in the Wheel Of Fate by spinning each time you level up on Ninja Kiwi. Bloonstones in Bloons Monkey City Mobile are shaped like a bloon and are red like the red bloon.
They are also able to be bought via NK Coins in the Flash version or real life currency in the Mobile version at the Premium store. For each Ninja Kiwi coin, the player is able to purchase 5, though the more NK Coins or currency the player decides to spend, the more bonus Bloonstones they will receive.
- Finishing a building or an upgrade of a building, or repairing a damaged building (1 minute = 1, but if it lasts more than 30 minutes, it is a bit different)
- Buying City Cash (Ratio: 40 = 1)
- Purchasing and spending extra Bloontonium (Ratio: 40 = 1 (Flash), 2% = 1 (mobile))
- Researching Lead Bloons and above
- Researching 3rd tier upgrades for 20 and 4th tier upgrades for 50 (in Mobile, no bloonstones are required if there is strong Wifi connection)
- Starting with extra cash in a battle (10, Flash only)
- Using a Continue (20)
- Adding Regrow Assault ( 15, Flash only)
- Adding Camo Assault ( 10, Flash only)
- Adding Extra Lead ( 10, Flash only)
- Adding Extra MOABs ( 10 or 15, Flash only)
- Making a MvM Attack stronger ( 10, mobile only)
- Restarting a MvM Attack (50, Flash only)
- Buying a supply crate (5, mobile only)
- Using a bonus tower (10, mobile only)
- Using a Monkey Boost to double the attack speed of all units for 10 seconds (5 on Flash, 10 on mobile).
- Buying a stack of 20 [to place on the track] (5)
- Currently, the cumulative cost to upgrade all monkey towers is (2520 plus cash), and (140 plus cash) to upgrade all MvM bloons.
- In Bloons Monkey City Mobile, Bloonstones look very different, as they look like a crystallized Red Bloon.
- Occasionally, a player may accidentally press the Monkey Boost when actually trying to get a tower, especially in the case of Mobile. This may make the player waste a Monkey Boost.
- Bloonstones are more difficult to get in the mobile version, as you only get two for completing a level with no lives lost, and there is no hardcore mode to double it.