From Minetest

A block in Minetest Game
Block Type Solid block
Drops Itself
Physics No
Luminance No
Flammable Yes
Generated Yes
Renewable Yes
Stackable Yes (99)
Itemstring default:cactus

Cactus can be found naturally in deserts.

It can be mined with an axe, not with bare hands and it can be placed anywhere. When a cactus block is mined, all connected cactus blocks directly above it are automatically mined as well.

A cactus which is on any kind of sand will slowly grow up to three additional cacti (blocks) above it when there is just air. Cacti need a light level of 13 or higher to grow. Cacti can thus be farmed.

A cactus can be used as fuel in the furnace. It does not deal damage to mobs and players touching it as you would expect a cactus to do.

See also