Stalactite

A stalactite is a rock that hangs from the ceiling of a cave and grows downward, one drip at a time. It holds on “tight”, which is how people remember it is not a stalagmite, and also how it remembers.^[1]

Stalactites grow at about the same speed as stalagmites, but in the opposite direction, so that the two can meet in the middle after roughly forty thousand years, or earlier if one of them gets impatient.

Hanging

A stalactite is the only rock that has never touched the ground. If it does touch the ground it is no longer a stalactite but a column, or, if it touched the ground suddenly, gravel. Geologists describe this as “retirement”.^[2]

Relationship with stalagmites

Stalactites and stalagmites spend their whole lives growing towards each other without speaking. In the Grotte de l’Attente, a pair separated by 1.1 centimetres has been watched since 1902; in 2019 the stalagmite reached up and touched it, and the stalactite is reported to have “seen it coming”.^[3]

A stalactite that freezes instead of dripping is an icicle, which is the same idea done in a single winter by someone in a hurry.

Safety

Visitors to caves are advised not to stand directly under a stalactite. Stalactites are advised the same about visitors, but cannot move.

See also

• Stalagmite – the one coming up
• Icicle – a stalactite made of ice, on a deadline
• Cave – the waiting room
• Ceiling – where it hangs out

References

1. Calcite, C. (1988). Holding On. Drip Press.
2. Speleology Board (1974). “Retirement of Stalactites: Guidance”.
3. Drip, D. et al. (1902–2019). “Are They Touching Yet?”. Field notes, four generations.