The Naked Scientists

The Naked Scientists Forum

Author Topic: Rock Identification for my Essay  (Read 10746 times)

Offline Vadermort

  • Full Member
  • ***
  • Posts: 60
    • View Profile
Rock Identification for my Essay
« on: 28/08/2006 03:36:04 »
I need some help with identifying these rocks.
Can anyone help me?

Rock 1

Rock 2

Rock 3

Rock 3 closer

Rock 4

b.s


 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1338
  • Thanked: 5 times
    • View Profile
Re: Rock Identification for my Essay
« Reply #1 on: 28/08/2006 04:46:49 »
your pictures are not entirely clear- could you add a description?  Are you studying metamorphic rocks?
Can you measure hardness, or see bedding or foliation?  Can you identify any of the minerals (quartz, mica, feldpar, amphiboles)?
Here's a real shot in the dark-
1.  looks like either quartz or calcite veining, the left hand side of the rock appears to have micaceous minerals- if so I would guess gneiss or biotite schist?
2.  Quartzite? Gneiss?  Mylonite?
3.  Muscovite schist?  black is probably biotite, white is either feldspar, quartz, or rock fragments.

With more information, I could possibly provide a more accurate identification and geologic processes.

Subduction causes orogeny.
« Last Edit: 28/08/2006 04:48:09 by Bass »
 

Offline Vadermort

  • Full Member
  • ***
  • Posts: 60
    • View Profile
Re: Rock Identification for my Essay
« Reply #2 on: 28/08/2006 06:15:19 »
Thanks for the help anyways. There are more pictures here. Unfortunately my camera got stolen after taking better pictures so im using a webcam.

Rock 4

This rock is flat and smooth with brown areas on it
Rock 4 closer

These are the brown areas
Rock 5

Looks like limestone with white insides. I will do chem. testing soon
Rock 6

Sorry for unclear image. It apears to have some pattern on the side that could be biological?
Rock 7

Rock 8

I think this is just quartz.
Rock 9

This rock is shiny on both sides.
Rock 9 Closer under light

Rock 10

Thanks.. no time have to go.

b.s
 

Offline Vadermort

  • Full Member
  • ***
  • Posts: 60
    • View Profile
Re: Rock Identification for my Essay
« Reply #3 on: 28/08/2006 06:23:57 »
Sorry..
Rock 9 is this rock


Rock 10 is this


Sorry for the confusion. Im very busy right now...Its ok ill check up all the rocks that it could be. The shiny on rock 3 is not muscovite. It looks shiny because it is under a light.

b.s
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1338
  • Thanked: 5 times
    • View Profile
Re: Rock Identification for my Essay
« Reply #4 on: 28/08/2006 17:55:10 »
4:  Brown areas are probably iron oxide (limonite)- hard to tell much else from the picture
5:  let me know after you check with acid
6:  possible shale/argillite/slate (depending on degree of metamorphism)
7:  gneiss? quartzite?  marble? (hard to tell much from photo)  can you recognize any minerals in the rock?
8: I think you are correct- looks like quartz
9:  muscovite schist
10:  Looks like quartz or calcite veining in the photo- do the veins fizz in acid?  What is the hardness?

Throw me a bone here- a bit more information.  Are you trying to identify these for a geology class?  If so, what types of rocks (sedimentary, igneous, metamorphic) are you studying?  do the rocks scratch easily- only slightly- or not at all?  Are there any distinct crystals?  have you tried acid (don't forget, if the rock is dolomite, you need to scratch the rock before you get a reaction- fizz)?  is there a distinct layering in any of these rocks?

Subduction causes orogeny.
« Last Edit: 28/08/2006 17:57:44 by Bass »
 

Offline Vadermort

  • Full Member
  • ***
  • Posts: 60
    • View Profile
Re: Rock Identification for my Essay
« Reply #5 on: 29/08/2006 06:16:20 »
Im a high school geography student. Not much of a geologist. These rocks came from a rock quarry in southern China and are probably metamorphic and sedimentary rock. There are crystals present in rocks, 1(black) 3(black) 9 (small and goldish) 8(the quartz) All rocks except 9 scratch easily. the others are harder than fingernail. I will do chemical tests with each rock this evening and get back to you in about 12 hours. I will be doing precipitation with NaOH for iron, and HCl acid for carbonates. Any ideas of other chemical tests?

b.s
 

Offline Vadermort

  • Full Member
  • ***
  • Posts: 60
    • View Profile
Re: Rock Identification for my Essay
« Reply #6 on: 30/08/2006 09:40:59 »
Testing with sodium hydroxide is done. Rock 9 made a white precipitate indicating either magnesium or Calcium, the latter more likely. There was a very small trace of green precipitate in rock 4 which indicates the small presence of iron. Thats all that hapened. the rest didnt have any precipitate.

b.s
 

Offline Vadermort

  • Full Member
  • ***
  • Posts: 60
    • View Profile
Re: Rock Identification for my Essay
« Reply #7 on: 30/08/2006 09:40:59 »
Testing with sodium hydroxide is done. Rock 9 made a white precipitate indicating either magnesium or Calcium, the latter more likely. There was a very small trace of green precipitate in rock 4 which indicates the small presence of iron. Thats all that hapened. the rest didnt have any precipitate.

b.s
 

The Naked Scientists Forum

Re: Rock Identification for my Essay
« Reply #7 on: 30/08/2006 09:40:59 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums