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Author Topic: Blue Crystalline Rock  (Read 4589 times)

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Pristine Crystalline

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Blue Crystalline Rock
« on: December 19, 2016, 04:51:02 PM »

Hello, please help me identify this blue crystalline rock. thank you.

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55fossil

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Re: Blue Crystalline Rock
« Reply #1 on: December 19, 2016, 05:04:13 PM »

   Looks like a piece from a feldspar matrix. Common to have feldspar minerals like quartz, skorl, amozonite and beryl among others. Picture does not show any blues on my screen. Do you have any location or other info on the rock?
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mirkaba

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Re: Blue Crystalline Rock
« Reply #2 on: December 19, 2016, 05:09:01 PM »

It looks like a piece of pegmatite. The quartz can be white or smokey. Usually has feldspar and mica in it.
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Pristine Crystalline

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Re: Blue Crystalline Rock
« Reply #3 on: December 19, 2016, 06:32:29 PM »

It was dug up in sandy soil while planting a tree on Long Island. it weighs 236 grams and measures approximately 7x6x5 cm. the colors range from very dark blue to light blue to grey with splashes of red and champagne. My understanding of quartz is that it has well-defined crystals that grow outward, in a somewhat radiating fashion like spikes. it has no cleavage between crystals. it is brittle with conchoidal fracture. i cannot see how the warped, blebby, amorphous crystals which weld to each other in this rock can have any likeness to quartz crystal habit. if you'd want to be more precise, then you should use the term silicon dioxide SiO2 rather than quartz. quartz is a misnomer for so many mineral assemblages. incidentally, the pinkish material on left side of the rock might be quartz polymorph coesite perhaps. from what i have researched, there is only one mineral that can take on any morphology - diamond. look at the light colored champagne blebs on the lower portion of the rock, as well as most everywhere else top to bottom. i have seen many images of diamond rough posted online that look very characteristically similar to this specimen. pegmatite is a granitic mass of many jumbled widely varying mineral content and usually found as massive slabs. i have a very thin sheet of mica which is very brittle and has a rather dull sheen. where is feldspar in this rock?  probably other replies henceforth will pose the question "then why do you ask us for help IDing this rock?" i guess i just want to see what people have to say.... forgive me for the length of this reply... 

i have other minerals i'd like to share here as well.... thank you.
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mirkaba

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Re: Blue Crystalline Rock
« Reply #4 on: December 19, 2016, 09:20:04 PM »

Wow..............
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Pristine Crystalline

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Re: Blue Crystalline Rock
« Reply #5 on: December 19, 2016, 10:08:48 PM »

Thank You Mirkaba for the Wow.......! how now oh why specifically did you Wow?
 
     some more photos (taken outdoors):

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Slabbercabber

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Re: Blue Crystalline Rock
« Reply #6 on: December 20, 2016, 04:41:26 AM »

Quartz only shows its' crystal habit when it grows in open space or liquid.  In massive quartz it will grow until it contacts another solid.  This is almost certainly massive quartz.  Check the hardness.
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vitzitziltecpatl

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Re: Blue Crystalline Rock
« Reply #7 on: December 20, 2016, 07:24:19 AM »

Yeah, SiO2 includes a lot alright. The Mindat page for Quartz is pretty good.

http://www.mindat.org/min-3337.html

Details there on the cryptocrystalline varieties, where the crystals are still there - just microscopic.

55fossil

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Re: Blue Crystalline Rock
« Reply #8 on: December 20, 2016, 08:44:27 AM »

   Thank you for the mineral lesson, BUT,  When the snow clears a little I will dig some of my quartz, non-typical by your definition, off my rock pile. I will also try to find some feldspar pegmatite which I dug in Idaho. Apparently the book you read only gave reference to one type of quartz which most people are familiar with. While my knowledge may be limited I have done a lot of field work and dug tons of silica based rocks and minerals. I will do my best to share some pictures and knowledge from the material I have at the shop. That is not to say you do not have a huge blue diamond in the rough.
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55fossil

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Re: Blue Crystalline Rock "good informational site"
« Reply #9 on: December 20, 2016, 07:19:52 PM »

   Here is a link to a site with great pictures of massive quartz from feldspars. It also has many other great pictures and info.
http://www.sandatlas.org/pegmatite/
Pristine;   Just what is it you are saying you think you have found? Your reply seems to say you know minerals very well and just want to know what less educated people might think your specimen is. Yes, pegmatites contain many minerals and mixtures of minerals. That is why you find rose quartz, smokey quartz and a host of other quartz combinations. Look at all the inclusions in quartz crystals. I dare say I believe your stone is a combination of many minerals.
   If you really have questions this is the place. If you just have time to waste ..........   Neal

PS:   Please do tell me what exactly your stone is. I do not mind learning.
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southerly

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Re: Blue Crystalline Rock
« Reply #10 on: December 21, 2016, 02:08:33 AM »

Looks like quartz to me, there is zero blue on my monitor but that may be due to camera not dealing with it. BTW the mineralogical requirement for quartz (and any other mineral for that matter) is the internal arrangement of (in this case SiO2) molecules not the external form, well defined crystal faces (which are a consequence of the internal arrangement) are not required and only occur where there is room for them to grow.

I am happy to be proven wrong if a few simple diagnostic tests rule quartz out as photo's are often a poor way to id rocks.

David
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