Rocks and Minerals Question Marathon

[starfield]

looks like... (Click to Show Hidden Text)

ulexite. It exhibits the internal reflection of light along its crystal axis, like a fiber optic cable.

Correct! Nice job

[hexagonaria]

everything i post seems to keep going on twice. the forum must love my posts

[hexagonaria]

yay!

image (Click to Show Hidden Text)

What are these formations made of?
[img]https://encrypted-tbn2.google.com/images?q=tbn:ANd9GcQJZPgqk_X4slF9dnGjzHUFWxo9H3AMxNN1OHXRsCpCx1KPh6aO[/img]

[starfield]

Answer (Click to Show Hidden Text)

Those are the white cliffs of Dover and they are made of chalf

[hexagonaria]

Yep! I can totally see that being a question at regionals.

[starfield]

Next images (Click to Show Hidden Text)

[img]http://wiki.biomine.skelleftea.se/wiki/images/thumb/a/a9/Leaching_of_chalcopyrite.jpg/600px-Leaching_of_chalcopyrite.jpg[/img]

[tornado guy]

Hmm, its colors remind me of azurite.

[starfield]

no.... (Click to Show Hidden Text)

azurite is blue...right?

[quizbowl]

Hmm (Click to Show Hidden Text)

Looks to me like a Chalcopyrite, but that's just me.  I was going to say Bornite, but usually that has much more of a darker color. :/

[starfield]

yay! (Click to Show Hidden Text)

Quizbowl is correct, I also always get confused when the image of Chalcopyrite is tarnished. Anyway, your turn!