How Fast Is Stalactite Formation?

Stalactites — the icicle-shaped formations hanging from cave roofs — grow at much the same rate as the stalagmites forming below them, around 0.13 mm per year. Some unusually active caves can produce a few millimetres per year, but this is rare.

A 1-metre stalactite represents thousands of years of patient mineral deposit.

• About the same pace as the stalagmite forming below it
• Roughly 1,000× slower than your hair grows