Rocksday

Tufa

Spongy limestone that precipitates from cool, mineral-rich springs and lakes.

Tufa specimen
Photo: Darla Sondrol, CC0, via Wikimedia Commons

How to identify tufa

  • Very porous and light, like a sponge.
  • Often coats plant stems and moss.
  • Fizzes in acid.

Often confused with

Where it's found

  • Mono Lake, California
  • Pyramid Lake, Nevada
  • Plitvice Lakes, Croatia

Uses

Garden and aquarium rock.

Rock tumbling

Not suitable for tumbling.

Did you know?

Mono Lake's famous towers are tufa that formed underwater around springs.

Think you could spot it from a blurry close-up?

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