Rocks and Minerals Question Marathon

[quizbowl]

Hmm (Click to Show Hidden Text)

It's probably either muscovite or a weird tremolite, but I'm leaning toward muscovite.

Not muscovite!

[pinkyfinger]

OK, then... (Click to Show Hidden Text)

Tremolite? Forms through metamorphism.

[quizbowl]

OK, then... (Click to Show Hidden Text)

Tremolite? Forms through metamorphism.

Yep!

[pinkyfinger]

It's the black mineral on top.

[quizbowl]

OMG I HAVE ONE (Click to Show Hidden Text)

Schorl?

[pinkyfinger]

Very nice. I was hoping to get confusion for sphalerite on that one, but you got it.

[quizbowl]

WARNING: THIS SPECIMEN ITSELF IS NOT ON THE LIST.

What group is this specimen in?
What crystal structure does it have?

[fishman100]

Answer (Click to Show Hidden Text)

Beryl, hexagonal crystal structure, silicate group?

[pinkyfinger]

Maybe (Click to Show Hidden Text)

I would say it's almandine because of the shape and how it occurs on the surface, except for the color, so... garnet? Garnets have cubic crystal systems.

[quizbowl]

Maybe (Click to Show Hidden Text)

I would say it's almandine because of the shape and how it occurs on the surface, except for the color, so... garnet? Garnets have cubic crystal systems.

Good job! Specifically it is Uvarovite.