Rocks & Minerals B/C

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piimasta314
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Re: Rocks & Minerals B/C

Post by piimasta314 » March 25th, 2013, 1:17 pm

2 minutes per question or 2 minutes per station? (and how many questions per station? Regionals was on average 2 questions per station, but state should be more, right?)
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Re: Rocks & Minerals B/C

Post by SciJ » March 25th, 2013, 5:04 pm

I have a couple of ID questions:

How do you differentiate between satin-spar and a ulexite that does not show its optic fiber property? How do you identify a non-hexagonal beryl? And is crystalline limestone just a limestone with visible crystals?

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Re: Rocks & Minerals B/C

Post by piimasta314 » March 26th, 2013, 6:47 pm

SciJ wrote:I have a couple of ID questions:

How do you differentiate between satin-spar and a ulexite that does not show its optic fiber property? How do you identify a non-hexagonal beryl? And is crystalline limestone just a limestone with visible crystals?
Satin-spar Gypsum is softer (you can scratch it with your fingernail) and the striations are duller.
For beryl, there's lots of identifying factors besides crystal shape...you can use the luster, fracture/cleavage, etc.
Crystalline limestone doesn't always have to have visible crystals.
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Re: Rocks & Minerals B/C

Post by SciJ » March 27th, 2013, 8:38 pm

piimasta314 wrote:Satin-spar Gypsum is softer (you can scratch it with your fingernail) and the striations are duller.
For beryl, there's lots of identifying factors besides crystal shape...you can use the luster, fracture/cleavage, etc.
Crystalline limestone doesn't always have to have visible crystals.
Thanks! So, what is crystalline limestone then?

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Re: Rocks & Minerals B/C

Post by piimasta314 » March 28th, 2013, 9:44 am

SciJ wrote:
piimasta314 wrote:Satin-spar Gypsum is softer (you can scratch it with your fingernail) and the striations are duller.
For beryl, there's lots of identifying factors besides crystal shape...you can use the luster, fracture/cleavage, etc.
Crystalline limestone doesn't always have to have visible crystals.
Thanks! So, what is crystalline limestone then?
Sorry, that last one wasn't very clear. Crystalline limestone is when CaCO3 recrystallizes in limestone that was already there. But sometimes the CaCO3 crystals are so small or just so dull that they're not easily visible. You can google some pictures. A lot of crystalline limestone is pretty dull and ugly, and you can't really see the crystals too well, but you might be able to find them through magnification.
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Re: Rocks & Minerals B/C

Post by iYOA » March 28th, 2013, 10:53 am

Does anyone want to set up a test exchange with me for rocks and minerals?

Clarification: I am only exchanging home-made tests(not illegal ones from invites) and all of my tests that get swapped will be uploaded to the wiki at the end of the season.
West Windsor-Plainsboro High School South

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Re: Rocks & Minerals B/C

Post by Cade » April 7th, 2013, 7:00 am

This one's a tough one. I found this mineral on a trail two weeks ago, and I still don't know what it is. I am leaning towards malachite, but what does anybody else think it is? I will answer questions about its property.
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Re: Rocks & Minerals B/C

Post by piimasta314 » April 7th, 2013, 10:12 am

it's a bit hard to tell from this angle. The green is most likely malachite; I can't think of anything else it could be since amazonite doesn't come in such a powdery form.
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Re: Rocks & Minerals B/C

Post by piimasta314 » April 7th, 2013, 10:17 am

There's a lot of cool looking minerals encrusted on this rock. I don't know what the white stuff is from the picture alone...Where did you find it?
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Re: Rocks & Minerals B/C

Post by Cade » April 7th, 2013, 1:21 pm

piimasta314 wrote:There's a lot of cool looking minerals encrusted on this rock. I don't know what the white stuff is from the picture alone...Where did you find it?
It doesn't matter where I got it from, because at regionals, my teammate found a stash of rocks & minerals a school obviously dumped onto the dirt (who knows why?). Well there was about 10 of us digging through snow and weeds finding topaz, jasper, many quartz, etc. Like I said before, I can answer questions about its physical properties.
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