Novembr 16-18—COLUMBIA, SOUTH CAROLINA: Annual show; The Columbia, SC Gem and Mineral Society; Fri. 10-6, Sat. 10-6, Sun. 12-5
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 Post subject: "Labradorite quartz".....check it out a must see
PostPosted: Mon Dec 17, 2012 6:19 am 
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Check out this video I did...some stop-motion and some regular video. I personally termed the "Labradorite quartz" =D> [-X (it's iridescent)

I have seen iridescence on quartz before but this particular specimen is unique because all the crystals have iridescence on each of the euhedral faces. I have never seen that before on a quartz specimen. Usually it's only on one crystal or on a couple faces on multiple crystals but never on all the crystals and on all the faces! This one was in my junk flats that I had passed over many times. It really amazes me the variety of different features and characteristics the quartz specimens show that come from Diamond Hill. I have been lucky enough to see many of the best collections of material from there and the variety is so unique and varied it never ceases to amaze me. The smoky and amethyst pretty much produce the same type stones with a few oddballs here and there but the odd pockets you find in and around the skeletal and amethyst pits can do some crazy things to crystals.


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 Post subject: Re: "Labradorite quartz".....check it out a must see
PostPosted: Fri Dec 21, 2012 12:50 am 
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I was hoping the "check it out a must see" would bring everyone in...LOL
[chirp]....[chirp]...chirp]... :mrgreen:

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 Post subject: Re: "Labradorite quartz".....check it out a must see
PostPosted: Fri Dec 21, 2012 1:08 am 
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I might call it iris quartz, no?
http://www.mindat.org/article.php/1335/Iris+Quartz
As labradorite is clearly defined as a variety of feldspar.


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 Post subject: Re: "Labradorite quartz".....check it out a must see
PostPosted: Fri Dec 21, 2012 3:35 pm 
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My question is whether it's true "Iris Quartz" as defined by the mindat article, or whether the iridescence is caused by the following (mentioned in the same article):

"Colorless quartz crystals displaying interference colours in reflected light on the surface, caused by extremely thin surface films of limonite or other natural minerals – the same effect as caused by thin oil films on a puddle of rainwater"

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 Post subject: Re: "Labradorite quartz".....check it out a must see
PostPosted: Fri Dec 21, 2012 5:27 pm 
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Very likely asurface feature as Rick suggests; "present on all faces" points to that; if it were due to internal structure one would expect it to vary with crystal orientation.

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Hans Durstling
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 Post subject: Re: "Labradorite quartz".....check it out a must see
PostPosted: Fri Dec 21, 2012 6:24 pm 
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Oh, that makes sense.
Maybe Jason will weigh in on it.


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 Post subject: Re: "Labradorite quartz".....check it out a must see
PostPosted: Fri Dec 21, 2012 6:58 pm 
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Would it have to be an actual surface feature? It kind of looks like it's within the stone, perhaps covered by another episode of crystal growth. I have a couple of quartz crystals with an orange coating which is beneath a layer of clear quartz--in my mind, this makes them a lot nicer because they're less likely to wear off.


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