Inactive Stone Block — terraria

Type	BlockMechanism
Placeable	✔️ (1 wide × 1 high)
Use time	15 (Very fast)
Rarity
Sell	2
Research	100 required

Type	BlockMechanism
Placeable	✔️ (1 wide × 1 high)
Use time	15 (Very fast)
Rarity
Sell	2
Research	100 required

Active Stone Blocks and Inactive Stone Blocks are blocks that act as mechanisms. A given pair behave as a single block whose presence can be switched "on" or "off" using wire and a trigger.

When triggered, an Active Stone Block becomes an Inactive Stone Block, and vice versa. Wires must pass through all Active/Inactive Stone Blocks that are to be triggered, and the wires must connect to a trigger, such as a pressure plate, Switch, or timer. These blocks are useful for creating traps, floodgates, hidden passages, drawbridges (e.g. over water, lava, or empty space), skybridges, and much more.

An Active Stone Block is a foreground object. This means it looks and behaves as an ordinary Stone Block, inhibits movement, allows entities to stand or walk on it, blocks light, and can stop liquids.
An Inactive Stone Block is a background object. While still visible, it looks like darker Stone Block, and behaves like furniture. It is essentially empty space, allowing the passage of players, items, liquids, light, etc.

Both the Active and Inactive versions can be crafted. Players will usually want to craft the Active version, as the Inactive blocks cannot be placed next to each other without the support of other adjacent foreground blocks. Active blocks do not have this shortcoming, and switching them to Inactive afterwards using wires will still have the same outcome.

Placing Active Stone Blocks, switching them to Inactive with wiring, then mining them and picking them up again, will yield Inactive blocks, and vice versa.

Active/Inactive Stone Blocks occur naturally in Boulder traps found in the Cavern layer, where Active blocks that are wired to pressure plates suspend a Boulder in the ceiling. An enemy or player walking on the plate cause the Active blocks to turn Inactive, allowing the Boulder to fall through and damage any player below it.

Crafting

Recipes

Result	Ingredients	Crafting station
Active Stone Block	Stone Block Wire	By Hand
Inactive Stone Block	Stone Wall4 Wire	By Hand

Notes

This behavior can be generalized to all blocks via an Actuator. It allows turning any block inactive via wiring.
- While Active and Inactive Stone Blocks are obtainable from the beginning of the game, Actuators require defeating Skeletron to gain access to the Mechanic.
Furniture placed on Active blocks that are turned Inactive will be freed and fall as dropped items. Blocks placed adjacent to them will remain in midair, the same as if the other blocks had been mined away.
Inactive Stone Blocks can be mined with a pickaxe or drill as normal. Furthermore, they will be freed by explosions.

Tips

When in a Hardmode biome, it can be easy to spot these naturally generated Active Stone Blocks if the surrounding blocks are in Corruption, Crimson or Hallow because, unlike regular stone blocks, they cannot be corrupted.
Even without the Mechanic (required to obtain wiring tools), this item still has use if harvested from naturally-occurring Boulder traps underground. The player can select this item in the hotbar to see a layout of all wires on screen, which is useful for detecting and avoiding natural traps. This feature is shared with Traps and Pressure Plates.
A vertical strip of three Active Stone Blocks wired to a nearby Switch or Lever serves as a good alternative to doors that only players can open. NPCs will not be able to use them to stray outside, and no enemy can ever open them. Note that this will not fulfill a house's entrance requirement, so at least one actual door will still be required in order for an NPC to move in (though the door need not lead "outside", and can merely open into another room of a larger structure). Using Blue Pressure Plates on either side causes the "door" to turn inactive for a moment, then return to active the very instant the player reaches the other side. As Blue Pressure Plates are only triggered by players, this can also keep Zombies and such out during a Blood Moon.
- It is also possible to make an airlock-type double door system using 3 Active Stone Blocks and 3 Inactive Stone Blocks (or 6 of one or the other and activating only one side inactive/active) while still only allowing access for players only. This is useful for underground housing to keep underground enemies out.
To conserve storage space, consider switching all Inactive Stone Blocks to Active Stone Blocks, or vice versa. This can easily save an inventory or storage slot by combining the stacks.