[img]http://rocks.comparenature.com/PImg/Anthracite25Med_300.jpg[/img]
1. Identify this specimen
2. What major group (Silicates, Hydroxides/Oxides, Igneous Rocks, etc.) does this specimen belong to?
3. Where is this most abundant?
1. Obsidian
2. Extrusive igneous rock
3. Usually where a lava flow meets water, as obsidian is formed by the extremely quick cooling of felsic lavas.
Incorrect, you want to look really carefully at the texture with this one. It's not glassy like obsidian. Yes it looks like obsidian, but this is what obsidian actually looks like, if you need it.
The image quality on this one isn't that great, which is probably why I jumped directly to obsidian. If it isn't, as you've stated, then my next guess would be coal of some sort, probably anthracite. That would make it a sedimentary rock found in areas where, a very long time ago, carbon-rich bogs and forests were.
I'm not sure that's correct either, it's kind of hard to tell from the image.
Re: Rocks and Minerals B/C
Posted: September 10th, 2017, 3:49 pm
by OrigamiPlanet
whythelongface wrote:The image quality on this one isn't that great, which is probably why I jumped directly to obsidian. If it isn't, as you've stated, then my next guess would be coal of some sort, probably anthracite. That would make it a sedimentary rock found in areas where, a very long time ago, carbon-rich bogs and forests were.
I'm not sure that's correct either, it's kind of hard to tell from the image.
Yea, I understand the quality isn't great, but then again not everything is always going to be easy. Your answer is right except for #2, it's actually not a sedimentary rock, it's a different type of rock. There's some controversy about anthracite, but from what I know, it isn't sedimentary.
Re: Rocks and Minerals B/C
Posted: September 10th, 2017, 4:35 pm
by whythelongface
I think the Official List has all varieties of coal under "Sedimentary".
Re: Rocks and Minerals B/C
Posted: September 10th, 2017, 4:40 pm
by OrigamiPlanet
whythelongface wrote:I think the Official List has all varieties of coal under "Sedimentary".
It does, but when I was at PA states, they informed us of anthracite being a metamorphic rock, instead of sedimentary. That's what I was anticipating for as an answer, but I'll count anthracite as sedimentary.
Your turn now.
Re: Rocks and Minerals B/C
Posted: September 10th, 2017, 5:21 pm
by whythelongface
[img]https://s-media-cache-ak0.pinimg.com/originals/88/b9/1d/88b91dda7bd9bbd79426efcc41579366.jpg[/img]
1. Name the mineral and provide its chemical composition.
2. Where is this mineral most commonly found?
3. What two qualities of this mineral make it slightly undesirable for jewelry?
Re: Rocks and Minerals B/C
Posted: September 10th, 2017, 6:52 pm
by dxu46
whythelongface wrote:
[img]https://s-media-cache-ak0.pinimg.com/originals/88/b9/1d/88b91dda7bd9bbd79426efcc41579366.jpg[/img]
1. Name the mineral and provide its chemical composition.
2. Where is this mineral most commonly found?
3. What two qualities of this mineral make it slightly undesirable for jewelry?
1. Topaz, Al₂SiO₄(F,OH)₂
2. Brazil
3. It is very hard to fashion without damaging it, and the color fades after exposure to light.
Re: Rocks and Minerals B/C
Posted: September 10th, 2017, 7:08 pm
by whythelongface
dxu46 wrote:
whythelongface wrote:
[img]https://s-media-cache-ak0.pinimg.com/originals/88/b9/1d/88b91dda7bd9bbd79426efcc41579366.jpg[/img]
1. Name the mineral and provide its chemical composition.
2. Where is this mineral most commonly found?
3. What two qualities of this mineral make it slightly undesirable for jewelry?
1. Topaz, Al₂SiO₄(F,OH)₂
2. Brazil
3. It is very hard to fashion without damaging it, and the color fades after exposure to light.
Correct! Your turn, and make it a rock question, I'm worse at Rocks than Minerals...
Re: Rocks and Minerals B/C
Posted: September 11th, 2017, 5:33 pm
by dxu46
whythelongface wrote:
dxu46 wrote:
whythelongface wrote:
[img]https://s-media-cache-ak0.pinimg.com/originals/88/b9/1d/88b91dda7bd9bbd79426efcc41579366.jpg[/img]
1. Name the mineral and provide its chemical composition.
2. Where is this mineral most commonly found?
3. What two qualities of this mineral make it slightly undesirable for jewelry?
1. Topaz, Al₂SiO₄(F,OH)₂
2. Brazil
3. It is very hard to fashion without damaging it, and the color fades after exposure to light.
Correct! Your turn, and make it a rock question, I'm worse at Rocks than Minerals...
Rocks it is.
[img]https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSru7QRo8nXuknKIhz6tDFiHTAOAn48r1RdJ0zpWkgVU29y9idb[/img]
1. This image is an example of what rock under a microscope?
2. What are the individual pieces called?
3. Does this specimen effervesce?
4. What is the composition of this rock?
Re: Rocks and Minerals B/C
Posted: September 11th, 2017, 6:19 pm
by whythelongface
dxu46 wrote:Rocks it is.
[img]https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSru7QRo8nXuknKIhz6tDFiHTAOAn48r1RdJ0zpWkgVU29y9idb[/img]
1. This image is an example of what rock under a microscope?
2. What are the individual pieces called?
3. Does this specimen effervesce?
4. What is the composition of this rock?
1. Diatomite/Diatomaceous earth
2. Diatoms
3. No, because it is siliceous, not calcareous
4. Silicon tests of diatoms