Rocks and Minerals B/C

[dxu46]

Remove the quotes portion. Also, make sure you have a | symbol after "Question".

Question (Click to Show Hidden Text)

[img]http://geology.com/minerals/photos/augite-crystal.jpg[/img]
1. Identify this mineral.
2. How did you identify it?
3. What is its chemical composition?
4. What is its luster?

Dunno what's wrong with the image... and accessing the link makes it obvious...

Answer (Click to Show Hidden Text)

1. Augite
2. Using its obvious 120 degree cleavage angle
3. (Ca,Na)(Mg,Fe,Al)(Al,Si)2O6 (Silicate of calcium, sodium, magnesium, iron, and aluminum)
4. Dull

Note: Much of this info is copied directly from my binder

[dxu46]

Remove the quotes portion. Also, make sure you have a | symbol after "Question".

Question (Click to Show Hidden Text)

[img]http://geology.com/minerals/photos/augite-crystal.jpg[/img]
1. Identify this mineral.
2. How did you identify it?
3. What is its chemical composition?
4. What is its luster?

Dunno what's wrong with the image... and accessing the link makes it obvious...

Answer (Click to Show Hidden Text)

1. Augite
2. Using its obvious 120 degree cleavage angle
3. (Ca,Na)(Mg,Fe,Al)(Al,Si)2O6 (Silicate of calcium, sodium, magnesium, iron, and aluminum)
4. Dull

Note: Much of this info is copied directly from my binder

I'll assume I'm right unless sg2themax responds within 24 hours.

[whythelongface]

Remove the quotes portion. Also, make sure you have a | symbol after "Question".

Question (Click to Show Hidden Text)

[img]http://geology.com/minerals/photos/augite-crystal.jpg[/img]
1. Identify this mineral.
2. How did you identify it?
3. What is its chemical composition?
4. What is its luster?

Dunno what's wrong with the image... and accessing the link makes it obvious...

Answer (Click to Show Hidden Text)

1. Augite
2. Using its obvious 120 degree cleavage angle
3. (Ca,Na)(Mg,Fe,Al)(Al,Si)2O6 (Silicate of calcium, sodium, magnesium, iron, and aluminum)
4. Dull

Note: Much of this info is copied directly from my binder

I'll assume I'm right unless sg2themax responds within 24 hours.

That appears to be right to me. I think you can just ask the next question if you'd like.

[dxu46]

Answer (Click to Show Hidden Text)

1. Augite
2. Using its obvious 120 degree cleavage angle
3. (Ca,Na)(Mg,Fe,Al)(Al,Si)2O6 (Silicate of calcium, sodium, magnesium, iron, and aluminum)
4. Dull

Note: Much of this info is copied directly from my binder

I'll assume I'm right unless sg2themax responds within 24 hours.

That appears to be right to me. I think you can just ask the next question if you'd like.

Question (Click to Show Hidden Text)

[img]https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcT3HP4C2YvRvVihQX8T0087wVTkO6-wRKnCG6T7KkX7SWPx0rpK[/img]
1. What is the rock?
2. What is the mineral?
3. Name the area where the rock is most commonly found.
4. What is the rock's plutonic equivalent.

[whythelongface]

I'll assume I'm right unless sg2themax responds within 24 hours.

That appears to be right to me. I think you can just ask the next question if you'd like.

Question (Click to Show Hidden Text)

[img]https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcT3HP4C2YvRvVihQX8T0087wVTkO6-wRKnCG6T7KkX7SWPx0rpK[/img]
1. What is the rock?
2. What is the mineral?
3. Name the area where the rock is most commonly found.
4. What is the rock's plutonic equivalent.

Answer (Click to Show Hidden Text)

1. Looks like a really bubbly basalt, even edging into scoria
2. Olivine
3. Basalt is a very prevalent rock in oceanic crust and mafic lava flows. Scoria is found as bombs and tephra from volcanic eruptions.
4. Gabbro

[ScottMaurer19]

That appears to be right to me. I think you can just ask the next question if you'd like.

Question (Click to Show Hidden Text)

[img]https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcT3HP4C2YvRvVihQX8T0087wVTkO6-wRKnCG6T7KkX7SWPx0rpK[/img]
1. What is the rock?
2. What is the mineral?
3. Name the area where the rock is most commonly found.
4. What is the rock's plutonic equivalent.

Answer (Click to Show Hidden Text)

1. Looks like a really bubbly basalt, even edging into scoria
2. Olivine
3. Basalt is a very prevalent rock in oceanic crust and mafic lava flows. Scoria is found as bombs and tephra from volcanic eruptions.
4. Gabbro

Probably vesicular basalt

[dxu46]

Question (Click to Show Hidden Text)

[img]https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcT3HP4C2YvRvVihQX8T0087wVTkO6-wRKnCG6T7KkX7SWPx0rpK[/img]
1. What is the rock?
2. What is the mineral?
3. Name the area where the rock is most commonly found.
4. What is the rock's plutonic equivalent.

Answer (Click to Show Hidden Text)

1. Looks like a really bubbly basalt, even edging into scoria
2. Olivine
3. Basalt is a very prevalent rock in oceanic crust and mafic lava flows. Scoria is found as bombs and tephra from volcanic eruptions.
4. Gabbro

Probably vesicular basalt

It's vesicular basalt. whythelongface, your turn!

[whythelongface]

Question (Click to Show Hidden Text)

[img]http://www.alexstrekeisen.it/immagini/diagrammi/feldspar.jpg[/img]
1. What is the unlabeled region in this triangular plot known as?
2. What is the difference between orthoclase and monocline?
3. Under a polarized thin section, what is the easiest way of differentiating plagioclase, monocline, orthoclase, and quartz?

[OrigamiPlanet]

Question (Click to Show Hidden Text)

[img]http://www.alexstrekeisen.it/immagini/diagrammi/feldspar.jpg[/img]
1. What is the unlabeled region in this triangular plot known as?
2. What is the difference between orthoclase and monocline?
3. Under a polarized thin section, what is the easiest way of differentiating plagioclase, monocline, orthoclase, and quartz?

Answer (Click to Show Hidden Text)

1. High temperature compositional region?
2. Orthoclase lacks lamellar twinning whilst microcline does, and microcline is the only one that can be in a darker color/blue-green.
3. Look for cleavage: If it lacks cleavage than it is likely quartz. I'm not sure with plagioclase, monocline and orthoclase other than the color composition.

[whythelongface]

Question (Click to Show Hidden Text)

[img]http://www.alexstrekeisen.it/immagini/diagrammi/feldspar.jpg[/img]
1. What is the unlabeled region in this triangular plot known as?
2. What is the difference between orthoclase and monocline?
3. Under a polarized thin section, what is the easiest way of differentiating plagioclase, monocline, orthoclase, and quartz?

Answer (Click to Show Hidden Text)

1. High temperature compositional region?
2. Orthoclase lacks lamellar twinning whilst microcline does, and microcline is the only one that can be in a darker color/blue-green.
3. Look for cleavage: If it lacks cleavage than it is likely quartz. I'm not sure with plagioclase, monocline and orthoclase other than the color composition.

Not really (Click to Show Hidden Text)

Admittedly this was a bit harder than usual.
1. The answer I was looking for was "Miscibility gap". This is a region on the triangular plot where no solid form of the chemical composition described there exists. In other words, there is a gap in mixing of different endmember elements.
2. Yes, but I was thinking of something more general, as in formation. Microcline is formed from the slow cooling of alkali feldspar species. It is also triclinic as opposed to microcline, which is monoclinic.
3. Under a cross-polarized microscope, one can readily see vertical lines in plagioclase minerals - that's because it twins following the albite law. Orthoclase crystals have more horizontal cleavage, which is also easily spotted. Microcline will usually have a grid-iron pattern of scratches on crystal surfaces. Quartz is more uniform, has a weaker and often undulatory birefringence pattern. What this means is that the extinction of cross-polarized light is not very apparent when you rotate the crystal.

Your turn.