Earth science

Find three groups of three connected words.

Mistakes left: ●●●●

Choose three words, then submit your group.

Puzzle notes

This original practice board has nine words and three intended categories. Look for specific shared meanings rather than a broad association. It is part of TrioNine’s 38-puzzle collection, published October 1, 2026.

Words on this board: GRANITE, BASALT, OBSIDIAN, WIND, WATER, ICE, CALDERA, CRATER, LAVA TUBE.

Reveal this puzzle’s three groups and explanations

Igneous rocks

GRANITE · BASALT · OBSIDIAN

These rocks form from cooled magma or lava.

Erosion agents

WIND · WATER · ICE

These move or wear away rock and sediment.

Volcanic features

CALDERA · CRATER · LAVA TUBE

These features are associated with volcanoes.

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