Tarnowitzite, a variety of aragonite. The hardness of crystals is measured using the Moh's scale. Diamond is the hardest, talc the softest.

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Build a volcano

Build a volcano, let it erupt, then build another

How many types can you make?

Pool of lava

Every volcano has a different character and style. What makes them different? It's all about the sort of lava that bubbles up inside.

Lava can be:

Runny or Sticky

and can contain

Lots of Water or Little Water

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