geode: Quick Facts

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Amethyst geode from Nova Scotia, Can.

A diagram displays illustrations of various common crystal aggregations and habits in minerals, including granular, lamellar, bladed, fibrous, acicular, radiating, dendritic, mammillated, colloform, stalactitic, geode, and oolitic forms, each labeled with mineral examples.

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chemical rock oölite nodule pisolite coal siliceous rock phosphorite evaporite banded-iron formation carbonate rock

Basalt sample returned by Apollo 15, from near a long sinous lunar valley called Hadley Rille. Measured at 3.3 years old.

(Bed) Rocks and (Flint) Stones