GeoJeopardy Fridays

I am starting up a new thing here, which is sort of a continuation of an old thing but on a schedule. It is GeoJeopardy! Fridays. Because who can't use a little trivia when your not doing work.

- Rocks and Minerals -

For its state mineral, Colorado chose rhodochrosite, which is a deep shade of this primary color

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Scoria, a dark, glassy rock created from this, is heavier than pumice & has bigger holes

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Galena is the principal ore of this metallic element, symbol Pb

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This blackboard rock is formed when shale is subjected to immense heat & pressure

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On the Mohs scale, this mineral can be scratched by every other mineral

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All the answers as well as any other previous GeoJeopardy! questions can be found over at my website by clicking the link.