Stalactites hang from the ceiling; stalagmites rise from the ground. The letters give it away: stalaCtite has a C for ceiling, stalaGmite has a G for ground. Both form from dripping mineral-rich water over very long periods.
The core difference
Two cave formations, distinguished by direction.
- stalactite — hangs down from the ceiling. C for ceiling.
- stalagmite — grows up from the ground. G for ground.
A second memory aid
Stalactites hold tight to the ceiling; stalagmites might reach the top one day. Either aid works — the point is that the pair needs one, because nothing about the words is intuitive.
How they form
Water carrying dissolved calcium carbonate drips through cave rock. Some mineral is deposited at the ceiling, building a stalactite downward; the rest lands below and builds a stalagmite upward. Where the two meet they form a column or pillar.
The Greek
Stalaktos means dripping; stalagma means a drop. Both from the same verb meaning to drip.
