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Desktop/Console/Mobile/Switch/tModLoader-Only Content: This information applies only to the Desktop, Console, Mobile, Switch, and tModLoader versions of Terraria.
Gem Locks
  • Amethyst Gem Lock.png Topaz Gem Lock.png Sapphire Gem Lock.png

    Emerald Gem Lock.png Ruby Gem Lock.png Diamond Gem Lock.png Amber Gem Lock.png

Stack digit 9.pngStack digit 9.png
Placeable✔️ (3 wide × 3 high)
Use time10 (Very fast)
RarityRarity level: 0

Placed Gem Locks, in both their on and off states.

A Gem Lock is a special mechanism which acts as a container or altar for a Large Gem. A Gem Lock will emit an activation signal if the corresponding Large Gem is placed inside it and once again if it gets removed. This allows for a simple contraption that uses only one mechanism to keep something like a door open as long as the gem is inside the lock, because if it gets taken out it will immediately close.

Gem Locks are primarily used in the making of adventure maps, where the player must complete some objective to be rewarded with the gem required to continue.



ResultIngredientsCrafting station
Amber Gem LockAmber Gem Lock
Internal Item ID: 3650
Heavy Work BenchHeavy Work Bench
Amethyst Gem LockAmethyst Gem Lock
Internal Item ID: 3648
Diamond Gem LockDiamond Gem Lock
Internal Item ID: 3649
Emerald Gem LockEmerald Gem Lock
Internal Item ID: 3646
Ruby Gem LockRuby Gem Lock
Internal Item ID: 3644
Sapphire Gem LockSapphire Gem Lock
Internal Item ID: 3645
Topaz Gem LockTopaz Gem Lock
Internal Item ID: 3647
total: 7 row(s)


  • The Gem Lock is the only craftable mechanism that emits a signal, while not having wire in the recipe.
  • Painting the Gem Lock will also affect the color of the gem placed inside it.
  • The Gem Lock only sells for 1, despite the ingredients being worth more.