Clash of Clans Wiki
Clash of Clans Wiki

Gem Mine9.png

"Gem Mines access a rare deposit of this highly valuable resource! Mining gems is slow and hard work."

Gem Mine Ruin.png Gem Mine1.png Gem Mine2.png Gem Mine3.png Gem Mine4.png
Ruin Level 1 Level 2 Level 3 Level 4
Gem Mine5.png Gem Mine6.png Gem Mine7.png Gem Mine8.png Gem Mine9.png
Level 5 Level 6 Level 7 Level 8 Level 9


  • The Gem Mine can be unlocked in the Builder Base. It requires Builder Hall 3 to be repaired.
  • When in disrepair, the Gem Mine is treated similarly to an obstacle (much like the ruined Clan Castle) and cannot be moved around; attacking troops will not be able to attack or destroy it (nor do they need to do so in order to achieve 100% destruction). Once rebuilt, it can be moved freely around.
    • However, troops cannot be deployed on top of it.
  • The Gem Mine, as its name suggests, produces Gems, albeit very slowly. These mined Gems are then stored until the player collects them or the storage fills.
  • Like other resource-producing buildings in both villages, upgrading the Gem Mine will disable production for the duration of the upgrade.

Defensive Strategy

  • This building serves no purpose on defense, so placing it on the outside to protect your defenses can be good.
  • Placing it in the corner can stall your opponent from getting three stars or losing time on your base.
  • This building has low hitpoints, so it is better to place it outside of the Walls or the base.

Upgrade Differences

  • Gem Mines undergo a significant visual change at levels 1, 3, 7, 8 and 9.
    • In its initial ruined state, it appears as a derelict, overgrown cave. A Gem insignia on a wooden hexagon on the side of the rocks can be found on the Mine's side. There are large broken wooden planks covering the entrance and a broken box. There are also Gems scattered around the Mine.
    • When reconstructed, the Gem Mine is a cave-like structure with a wooden arch supported by ropes at the entrance. The Gem insignia is present on the side of the Mine, and a rail conveyor extends out of the cave, into a box containing Gems. Outside the cave is a torch.
    • At level 2, the Gem Mine's arch and base are reinforced by metal. The grass on the side of the Gem Mine has disappeared.
    • At level 3, the top of the cave is replaced by an open roof and a pulley system. More wooden planks are added to the sides of the opened roof, in order to support the pulley. Additional reinforcing metal plates appear at the top of the entrance.
    • At level 4, the reinforcing metal plates change to a bronze-colored scheme. A second pulley is also added.
    • At level 5, the reinforcing wooden structure now extends to the back of the cave, and additional bronze plates are added to the backside of the roof.
    • At level 6, the pulley system becomes bronze, with wood covering the roof.
    • At level 7, a bar is fixed to the roof, and it now suspends the pulley system. Ropes can be seen between the two pulleys, and the roof now appears to be made of stone. The Gem Mine receives a stone base with more support.
    • At level 8, the wooden supports at the corners are replaced with larger wooden beams. The beams are slanted and support a new pulley system consisting of one large pulley with its bar attached to the roof by bolts.
    • At level 9, the bases of the supports at the corners have been replaced with iron bases, and the pulley system on top has been replaced with a larger one.


November 6, 2012 The Gem Mine was suggested by escoangel on forums.
Patch Description
May 22, 2017 Added the Gem Mine, with 5 levels.Gem Mine1.pngGem Mine2.pngGem Mine3.pngGem Mine4.pngGem Mine5.png
June 27, 2017 Added the level 6 Gem Mine.Gem Mine6.png
September 27, 2017 Added the level 7 Gem Mine.Gem Mine7.png
March 5, 2018 Added the level 8 Gem Mine.Gem Mine8.png
December 10, 2018 The level 3 Gem Mine can now be upgraded at Builder Hall level 3. Previously it required Builder Hall level 4.
June 18, 2019 Added the level 9 Gem Mine.Gem Mine9.png


  • There are no storages for the Gems except for the Gem Mine due to your unlimited Gem inventory.
  • Unlike the Gold Mine, there is no cart that delivers the Gems to the surface. Instead, a conveyor belt delivers the Gems to the surface and deposits them into the box at the entrance.
  • At level 8, to get the worth of a bundle; it takes 16 days to get 80 Gems and up to a staggering 7 years to get 14,000 Gems.
  • At max level, it produces 4.8 Gems per day. In a longer prospective, a max level Gem Mine will generate 1,752 Gems in one non-leap year, and 1,756.8 Gems in a leap-year.
  • When a maxed Gem mine is paired with a maxed Clock Tower or a Clock Tower Potion one boost will net a player 90% of a gem.

Icon Descriptions

Icon Info.pngTapping this icon displays information about the Gem Mine, such as Level, Capacity, Production and Hitpoints.
Icon Upgrade.pngTapping this icon begins upgrading the Gem Mine to the next level, if you have enough resources and a free Master Builder or O.T.T.O. When the Gem Mine is at maximum level, this icon is not shown.
Icon HoB.pngTapping this icon instantly upgrades the Gem Mine to the next level, at the cost of one Hammer of Building if you have one. When the Gem Mine is at maximum level, or the Builder Hall requirements for the next level are not met, this icon is not shown.
Icon FinishNow.pngTapping this icon, which is displayed only while an upgrade is in progress, instantly finishes that upgrade at the cost of the displayed number of Gems.
Icon FinishNowBoB.pngTapping this icon, which is displayed only while an upgrade is in progress, instantly finishes that upgrade at the cost of one Book of Building. This icon is only shown if you have at least one Book of Building.
Icon FinishNowBoE.pngTapping this icon, which is displayed only while an upgrade is in progress, instantly finishes that upgrade at the cost of one Book of Everything. This icon is only shown if you have at least one Book of Everything but do not have a Book of Building.
Icon Cancel.pngTapping this icon, which is displayed only while an upgrade is in progress, cancels the current upgrade and refunds half of the upgrade cost.
Builder Hall Level 1 2 3 4 5 6 7 8 9
Number Available 0 0 1 1 1 1 1 1 1
Size Size
Production Rate (per day)*
Production Time per Gem
Time to Fill
Build Cost
Builder Elixir
Build Time
Experience Gained
Catch-up Point** Builder Hall Level Required
Builder Hall
1 10 2.16 11h 6m 40s 4d 15h 6m 40s 300 120,000 1h 60 N/A 3
2 11 2.40 10h 4d 14h 345 180,000 2h 84 18h 3
3 12 2.64 9h 5m 27s 4d 13h 5m 27s 397 240,000 6h 146 2d 12h 3
4 13 2.88 8h 20m 4d 12h 20m 457 450,000 8h 169 3d 16h 4
5 14 3.12 7h 41m 32s 4d 11h 41m 32s 526 1,000,000 10h 189 5d 5
6 16 3.36 7h 8m 34s 4d 18h 17m 9s 605 1,500,000 12h 207 6d 12h 6
7 18 3.84 6h 15m 4d 16h 30m 696 2,500,000 1d 293 7d 7
8 20 4.32 5h 33m 20s 4d 15h 6m 40s 800 3,500,000 2d 415 16d 8
9 22 4.80 5h 4d 14h 840 4,500,000 3d 509 27d 9

* These values are exact values that are derived from the game files. In-game, this statistic is rounded down to one decimal place.

** The Catch-Up Point is the time at which the newly upgraded Gem Mine has equaled the total production of the mine had it not been upgraded - this does not consider recovering the cost of the Builder Elixir required to perform the upgrade.

Caveat: The Catch-Up Point calculation assumes that the player collects all resources from the Gem Mine without allowing it to reach its storage capacity, as resource production ceases at that point. If the player is unable to regularly collect and achieve the full potential of the collector, the Catch-Up Point is actually shorter and performing the upgrade becomes more advantageous.

Builder Base Buildings
Defensive Buildings CannonDouble CannonArcher TowerHidden TeslaFirecrackersCrusherGuard PostAir BombsMulti MortarRoasterGiant CannonMega TeslaLava LauncherWalls
Traps: Push TrapSpring TrapMineMega Mine
Resource Buildings Builder Hall (Magic Items) • Gold MineElixir CollectorGold StorageElixir StorageGem MineO.T.T.O Hut
Army Buildings Builder BarracksArmy CampStar LaboratoryBattle Machine Altar
Other Buildings BoatDecorationsObstaclesClock Tower