Rocks and Minerals B/C

[havendude]

how would you guys suggest studying for the rock and mineral ID portion of the test?

Tuftedtitmouse12 is right, it will be really helpful if you get your own box(es) of specimens. I would also suggest going to the Scioly rocks ID discussion and going through that several times.
The most important thing (I think) is to use pneumonic devices on the rocks. When I just started learning them, I took a rock, found something unique about it, and then made a stupid name of it. The stupider the better, because you can remember it better. For instances, with Aragonite, I found that in most samples it was very milky white. Therefore:
Aragonite==>sounds like==>Aragorn
Aragorn==>was in LOTR and got the http://en.wikipedia.org/wiki/Dead_Men_of_Dunharrow on his side
Dead Men of Dunharrow==>have the same skin coloration as==>Aragonite

Stupid, I know. But I can always recognize Aragonite because of that order.

I made sequences like that with almost every rock and mineral on the list (except for the really obvious ones), in a relatively short time.

[eox]

Google images.

But what I like to do is try to find a distinguishing characteristic for each mineral or rock, but that's not always easy. I would be really helpful if you could get your hands on some real specimens

if i were to get real specimens, what should i do with them besides get familiar with their heft / certain features?

[tuftedtitmouse12]

Google images.

But what I like to do is try to find a distinguishing characteristic for each mineral or rock, but that's not always easy. I would be really helpful if you could get your hands on some real specimens

if i were to get real specimens, what should i do with them besides get familiar with their heft / certain features?

You can see their features up close. You see, pictures can only show you so much. Then can only go into their macro setting so much and you can only see some details. Once you know how a true specimen feels and looks up close, it will be much easier to point them out in a picture. Besides, when you look at a picture, you only see one side of the specimen. With a 3D object, you can turn it over and thoroughly examine it. Especially for minerals, crystal structure and all those traits are easiest learned not from reading, but from actually seeing it and feeling it.


Basically, specimens are the real thing. If you can get specimens, it's no big deal to get pictures (Google images) and you'll be more prepared for competition, where you may get either specimens, pictures, or both.

Edit: Just out of curiosity, but have you done this event before?

[eox]

how would you guys suggest studying for the rock and mineral ID portion of the test?

I would also suggest going to the Scioly rocks ID discussion and going through that several times.

Is it a seperate subform? Thanks for the mnemonic device idea, too! its really helpful!
EDIT: Do you mean Rocks and Minerals Question Marathon? (http://scioly.org/phpBB3/viewtopic.php?f=121&t=3036)

You can see their features up close. You see, pictures can only show you so much. Then can only go into their macro setting so much and you can only see some details. Once you know how a true specimen feels and looks up close, it will be much easier to point them out in a picture. Besides, when you look at a picture, you only see one side of the specimen. With a 3D object, you can turn it over and thoroughly examine it. Especially for minerals, crystal structure and all those traits are easiest learned not from reading, but from actually seeing it and feeling it.
Edit: Just out of curiosity, but have you done this event before?

No i haven't, its my first year
What about the variations on color / habit of a rock though? Would you have to get multiple samples for each variant, or is just one sufficient.
What traits do you guys normally use for ID?

[tuftedtitmouse12]

Oh yes, the marathon. If I were you, read through them, and see if you can try doing some yourself!

Color is really not your best bet, especially for minerals. There, I like to use crystal structure and the texture, luster, stuff like that. That's really why having actual specimens in your hands help. Then you get the whole feel of the mineral. For rocks, the color is a bit more reliable. For instance, gabbro looks like speckles of green and black while diorite is salt and pepper. Then there's granite, which is usually white, clear, and black, those three being the base colors. The white being feldspar, clear quartz, and black mica.

Basically, examine the specimens, try to connect the name to the mineral or rock, NEVER the shape or size of your specimen, and once you've spent enough time, you'll start to see the differences. It helps if you can hold two specimens that look alike and compare them to each other.

The specimens are to get the general idea. There's always pictures on google if you needed to find the color variants and such. I hope this helps!

[havendude]

What about the variations on color / habit of a rock though? Would you have to get multiple samples for each variant, or is just one sufficient.
What traits do you guys normally use for ID?

You only really need one sample of a rock, but it always helps to have more. If you only have one sample, you will just have to research the rock on google. Wikipedia is also really helpful, because they usually have articles that outline every variation. Plus, the rocks that you will get grilled on the most (fluorite, calcite, etc.) generally have long articles, because they're complicated or very common.

For ID, I use crystal structure the most, followed by texture, and then density. It also helps to know what shades of colors they are (dark vs. light), and their translucency. Some you can tell automatically just from one or two traits. Galena (the heaviest for its size,) for instance, or graphite (rubs off on your skin).

On the side, I think next year they might be introducing the history of geologic discovery to the possible topics. The nationals test had some questions about Mohs that I think most people weren't expecting. We had the answer in our field guide, but that doesn't always happen. I wouldn't count on it, but if you have some extra time, go Wikipedia hopping and get a paragraph or so on the major discoveries and geologists.

[hotchocolate123]

Hey, anybody know the "official" chemical formula for the mineral apatite? There are so many different varieties of the chemical formula i don't even know which one is "real"....

[Paleofreakazoid]

Hey, anybody know the "official" chemical formula for the mineral apatite? There are so many different varieties of the chemical formula i don't even know which one is "real"....

I think Apatite is a mineral group, so its individual members will have different formulas (e.g. fluorapatite and chlorapatite). What kinds of formulas are you finding?

[aim4me26]

Hey, anybody know the "official" chemical formula for the mineral apatite? There are so many different varieties of the chemical formula i don't even know which one is "real"....

I think Apatite is a mineral group, so its individual members will have different formulas (e.g. fluorapatite and chlorapatite). What kinds of formulas are you finding?

^That's right. I think that there are only individual formulas; I don't know about the group as a whole though.
For example, (CaF) or Flourapatite is Ca5(PO4)3F, while (CaCl) or Chlorapatite is Ca5(PO4)3Cl.

[hotchocolate123]

Hey, anybody know the "official" chemical formula for the mineral apatite? There are so many different varieties of the chemical formula i don't even know which one is "real"....

I think Apatite is a mineral group, so its individual members will have different formulas (e.g. fluorapatite and chlorapatite). What kinds of formulas are you finding?

^That's right. I think that there are only individual formulas; I don't know about the group as a whole though.
For example, (CaF) or Flourapatite is Ca5(PO4)3F, while (CaCl) or Chlorapatite is Ca5(PO4)3Cl.

Ohh.... thanks, but like I've been using the one on the Audubon field guide which is like the group formula --> [Ca5(PO4)3(F,Cl,OH)] then there's one on wikipedia that says the group is Ca10(PO4)6(OH,F,Cl,Br)2 and then when you purchase the science olympiad rock kit it comes with like a mini field guide which then says that the mineral apatite is Ca5(Cl,F)(PO4)3 ... I am sticking to the Audubon because it's an "official" published resource, and then most teachers tell you to NEVER use wikipedia... so...