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23 Sep-11:19:18 Re: help me identify these rocks/minerals (Alfredo)
23 Sep-11:03:35 Re: help me identify these rocks/minerals (Borg_jos)
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23 Sep-10:52:47 Re: help me identify these rocks/minerals (Mike Chontofalsky)
23 Sep-10:22:52 Re: help me identify these rocks/minerals (Bob Harman)
23 Sep-10:14:27 Help me identify these rocks/minerals (Borg_jos)
23 Sep-09:14:30 Re: collection of heimo hellwig (Heimo Hellwig)
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23 Sep-04:10:54 Re: new generation for picture - ploum (Ploum)
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23 Sep-01:39:10 Re: the mim museum in beirut, lebanon (Tobi)
23 Sep-01:36:07 Re: the mizunaka collection (Tobi)
22 Sep-17:22:54 Re: franjungle collection (Franjungle)
22 Sep-14:45:44 The mizunaka collection - fluorite (Am Mizunaka)
22 Sep-10:22:43 Re: someone told me this is what happens to mud at the bottom of a lake (Bob Carnein)
22 Sep-10:14:32 Re: someone told me this is what happens to mud at the bottom of a lake (Vic Rzonca)
22 Sep-08:12:37 Re: the mim museum in beirut, lebanon (Mim Museum)
22 Sep-04:26:22 Re: exchange of minerals. I'm from ukraine. (Hereiam)
22 Sep-04:01:14 Re: collection of manuel mesa (Manuel Mesa)
22 Sep-03:03:15 Re: exchange of minerals. I'm from ukraine. (Hereiam)
22 Sep-02:00:57 Exchange of minerals. I'm from ukraine. (Hereiam)
21 Sep-18:11:48 Re: need help identifying this rock (Gone Fishing)
21 Sep-18:10:17 Need help identifying this rock (Gone Fishing)
21 Sep-15:27:52 Re: collection of michael shaw (Crosstimber)

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Rock or Mineral?
  
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pin130




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PostPosted: Sep 05, 2017 18:46    Post subject: Rock or Mineral?  

I'm a relative beginner. I picked up a Moh's hardness test, a digital scale to measure
specific gravity and a good video on mineral identification. All ready to go, just one little
problem. If only a pure mineral can be identified through determinative tables and not a rock,
if you don't know if you've got a rock or a mineral at hand, where do you start? I'm not
talking about obvious minerals with visible crystal structure, such as I picked up in Franklin,NJ. I'm talking about plain old stones you find in your backyard.
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alfredo
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PostPosted: Sep 05, 2017 21:41    Post subject: Re: Rock or Mineral?  

Welcome to this forum!

Does it look homogeneous or does it look like a mixture of different kinds of grains?
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pin130




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PostPosted: Sep 05, 2017 22:56    Post subject: Re: Rock or Mineral?  

Do you mean to say that a homogeneous looking stone, i.e. of one color and texture, is a mineral, while one with different grains is a rock? How would you define the word "grain"?
I find both types if I understand your use of the word grain. Are their any articles or books to help answer this question? I find field guides useless since they show ideal mineral specimens and not the typical stones around the house. Thanks for your help.
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alfredo
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PostPosted: Sep 06, 2017 00:54    Post subject: Re: Rock or Mineral?  

A rock is composed of minerals, like the ingredients in a cake. Some rocks can be monomineralic, composed of only one mineral, so then your specimen is both a mineral and an example of that rock type at the same time. So think of the minerals as the ingredients in a cake, and a few kinds of cake might have only one ingredient, like baked oatmeal, and then be very boring cakes.
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pin130




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PostPosted: Sep 06, 2017 09:50    Post subject: Re: Rock or Mineral?  

Is there a book which you could recommend to help clarify these things. As I mentioned I find field guides useless because they don't describe actual "on the ground" questions
dealing with far from perfect specimens. I'm still left with the question is this stone an
identifiable mineral or a combination of minerals which cannot be tested with the usual methods. And it can't be identified through testing, how can you know what it is without
showing it to an expert? Thanks for your help.
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vic rzonca




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PostPosted: Sep 06, 2017 11:56    Post subject: Re: Rock or Mineral?  

pin130 wrote:
I'm still left with the question is this stone an
identifiable mineral or a combination of minerals which cannot be tested with the usual methods. And it can't be identified through testing, how can you know what it is without
showing it to an expert? Thanks for your help.


We're not saying it can't be tested. Every mineral can be tested and every rock can be identified. We make rock identification on Mars for heavens sake. Most mineral ID books have a section on rock types and you have to rely on familiarity with the looks of things. How something looks tells the interested observer quite a bit.There is a section on rock types on this site, take advantage of it. Take a look at illustrations in field guides and rock and mineral books. The Simon and Schuster guide has such a section. Every rock has an environment that it forms in and being aware of that will add to the database you need to make a field ID. Start with rock types, igneous, metamorphic, sedimentary, get to know what you are looking at. Pretty sure we all started out with that first encounter with something that looked different or worthy of further investigation, and so now you have. Time to investigate. Elementary my dear Watson. .



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Rock types that may be underfoot.
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