The Naked Scientists

The Naked Scientists Forum

Author Topic: what kind of rock or mineral is this  (Read 4452 times)

Offline mussina

  • First timers
  • *
  • Posts: 5
    • View Profile
what kind of rock or mineral is this
« on: 09/11/2012 04:49:30 »
Hi  I'm Chris and I am new on here,  I am trying to identify what kind of rock or mineral this is.  It has what appears to be quartz or crystal in it and it is a dark green color rock.  Thank you for your help
« Last Edit: 09/11/2012 06:02:56 by mussina »


 

Offline RD

  • Neilep Level Member
  • ******
  • Posts: 8122
  • Thanked: 53 times
    • View Profile
Re: what kind of rock or mineral is this
« Reply #1 on: 09/11/2012 06:45:53 »
Looks like Copper Ore ...


http://stabilityline.com/catalog.html


The deep blue could be azurite ...

Quote
While not a major ore of copper itself, the presence of azurite is a good surface indicator of the presence of weathered copper sulfide ores. It is usually found in association with the chemically very similar malachite, producing a striking color combination of deep blue and bright green that is strongly indicative of the presence of copper ores.
https://en.wikipedia.org/wiki/Azurite#Prospecting
« Last Edit: 09/11/2012 07:28:25 by RD »
 

Offline Bill S

  • Neilep Level Member
  • ******
  • Posts: 1802
  • Thanked: 11 times
    • View Profile
Re: what kind of rock or mineral is this
« Reply #2 on: 09/11/2012 14:19:03 »
Hi, Mussina.  Welcome to the "guess what this is" community. :)

To give you any real help, it would be necessary to have a bit more information, especially hardness and streak.  Sodalite is not uncommon and can look a bit like the blueish part of your specimen. 
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1338
  • Thanked: 5 times
    • View Profile
Re: what kind of rock or mineral is this
« Reply #3 on: 09/11/2012 18:48:43 »
To give you any real help, it would be necessary to have a bit more information, especially hardness and streak.

I agree with Bill S, more information would help positively identify the rock.  But just based on the photos, I think RD is on the right track- blue is probably azurite and green is probably malachite.  Both are weathering products of copper.
 

Offline Bill S

  • Neilep Level Member
  • ******
  • Posts: 1802
  • Thanked: 11 times
    • View Profile
Re: what kind of rock or mineral is this
« Reply #4 on: 10/11/2012 00:23:00 »
I agree; the combination of blue and green suggests copper.  Copper weathering products do tend to be a bit confusing.  Years ago, in Cornwall, I found what I took to be malachite. I later discovered it was atacamite.
 

Offline mussina

  • First timers
  • *
  • Posts: 5
    • View Profile
Re: what kind of rock or mineral is this
« Reply #5 on: 10/11/2012 04:45:54 »
Hi and thank you for the information.  How can I tell what the hardness and streak is.  I am a novice when it comes to knowing about this stuff.  I have added another picture.  Hope this helps and give me as much information so I can learn

Thank you
 

Offline mussina

  • First timers
  • *
  • Posts: 5
    • View Profile
Re: what kind of rock or mineral is this
« Reply #6 on: 10/11/2012 05:07:34 »
One more thing even though it looks blue.  It is actually a dark green color almost tourquoise or dark tourquoise
 

Offline mussina

  • First timers
  • *
  • Posts: 5
    • View Profile
Re: what kind of rock or mineral is this
« Reply #7 on: 10/11/2012 05:38:06 »
If I did the hardness test correctly it does leave a scratch in my fingernail.  It left a good scratch in a penny and it did scratch one of my steak knives.  I don't have a streak plate so is there anything else I can use.  Is there any other things I can use for the hardness test.

Thank you
 

Offline Bill S

  • Neilep Level Member
  • ******
  • Posts: 1802
  • Thanked: 11 times
    • View Profile
Re: what kind of rock or mineral is this
« Reply #8 on: 11/11/2012 15:35:25 »
Donít worry too much about a streak plate; they are really only unglazed tiles, so are of use only with the soft end of minerals.

When I was actively involved in the hobby I always carried with me a knife with a good steel blade and a piece of quartz.  With a bit of practice you can do most of your hardness and streak testing with those.

If you try scratching your specimen in various places with a bit of known quartz, and also try scratching the quartz with different parts of the specimen you will have a reasonable idea of its hardness, and if it is all the same material.

Obviously, there is nothing like having the specimen in your hand, and appearance is often a poor guide, but I am beginning to suspect that it might be one of the many varieties of cryptocrystalline quartz.  Go for it with a bit of quartz and that could be another wild guess out of the window.  :)



 

Offline mussina

  • First timers
  • *
  • Posts: 5
    • View Profile
Re: what kind of rock or mineral is this
« Reply #9 on: 12/11/2012 00:08:16 »
Hi Bill and thank you for responding back.  You have helped me to look in a different direction and I was wondering if you could take a look at chrysoprase and see if it bears some resembelence to what I have.  I am currently living in Cairns Australia and I am looking at finding who I can take it to to see if they would know.

Again thank you and you have been a great help

Chris
 

Offline Bill S

  • Neilep Level Member
  • ******
  • Posts: 1802
  • Thanked: 11 times
    • View Profile
Re: what kind of rock or mineral is this
« Reply #10 on: 12/11/2012 03:17:33 »
Chrysoprase was one of the things I had in mind when I mentioned cryptocrystaline silica.  My (43 year old) copy of Rutley's Elements of Mineralogy describes it as apple green, and you know how variable apples are. :)

Another, if not very likely, possibility is jasper.  Although it is normally brown, red or yellow, there is a dark green form which is quite rare.

A museum is often a good place to look for a geologist, and they are usually willing to help.

I hope you will let us know if/when you do get a definite verdict.
 

Offline Bill S

  • Neilep Level Member
  • ******
  • Posts: 1802
  • Thanked: 11 times
    • View Profile
Re: what kind of rock or mineral is this
« Reply #11 on: 12/11/2012 14:49:53 »
Hi Chris, I found this among my emails today; it may not help with the identification of your specimen, but I thought it was quite interesting.

http://geology.about.com/od/more_sedrocks/qt/About-Chert.htm?nl=1

 

The Naked Scientists Forum

Re: what kind of rock or mineral is this
« Reply #11 on: 12/11/2012 14:49:53 »

 

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