How Fast Is Stalagmite Growth?

Cave stalagmites grow by accumulating mineral deposits dripped from the ceiling — roughly 0.1 mm per year on average. The motion is among the slowest measurable processes anywhere on Earth, yet over enough time it builds entire underground forests of stone.

A 1-metre stalagmite represents an extraordinarily long span of patient dripping.

• About the same pace as fingernails growing
• Roughly 1,000× slower than grass grows