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Colorado Prospector - Gem and mineral prospecting and mining forums > Prospecting, Mineral Collecting and Treasure Hunting Forums > Gem and Mineral Specimen Finds or Processes
Pdrmastertech
Hello my wife and I just moved to beautiful Colorado and always talked about getting here and prospecting as a hobby...... Well.....last weekend we decided to head out and give it a go.
We decided on the Bear Creek, Cheyenne Canyon/ Mountain and Lake George areas.
No luck on Cheyenne MT.... No luck in Bear Creek..... But when we went to Lake George we found some interesting specimens. We're noobs and just starting out so bear with us if say something silly lol.
We were looking for Amozonite and pretty sure we found some.... I'll post some pics here.
While searching we came across a smoky quartz crystal just lying on the ground next to some previous digs.... Will post a pic of that as well.
What has us confused is this little piece that looks as if it's sandstone with clear dark blue spots throughout....when wet the entire piece turns blue!
Will post a pic of that as well.....my gut tells me that maybe it's man-made but I'm not sure..... ANY help would be great.... Thank You in Advance.
The wife and I are excited to be here and be a part of this.... One of our dreams :)
Pdrmastertech
These are the pieces we found.
Woody
Hi Pdrmastertech,

You nailed it on the Smoky and Amazonite. That bluish piece sure looks cool. I haven't seen anything like it to compare to coming from that area. The last two pics you posted do look like melted
glass. The chevrons could be some sort of contact transfer while the material was still hot. That blue piece is very interesting. It could be glass but there is two different materials inside and they did
not both melt together. Someone might have purposefully made this, kind of like making a decorative ceramic or something. Interesting, but without looking at it in hand I would guess man-made.

Be sure you do a land research in the places you are collecting. Have a good one, Woody.
ASTROBLEME
Hello Pdrmastertech,

Welcome! I'm certainly glad to see you've become a paid member and would like to assist with the ID of the unknown blue mineral specimen.

In my opinion, the dark blue shaded specimens appears to be a variety of Anorthite called Labradorite. This mineral type is known to occur in Gunnison County, Colorado within the Willow Creek Mining District and other nearby localities. I have quite a bit of prospecting experience across the Gunnison area due to my discovery (many years ago) and ongoing research of a large meteorite impact structure that I named Gunnison Crater. The pic you show looks very similar to what I've seen in Gunnison County.

Your find may be of some significance because it is quite distant from the known Gunnison locations. Here's a link you'll find helpful...

Labradorite Info

Sincerely,

ASTROBLEME
Gene Kooper
QUOTE (ASTROBLEME @ Oct 21 2016, 05:46 PM) *
a variety of Anorthite called Labradorite.

Not to pick nits, but labradorite is not a variety of anorthite. The mindat.org reference by Paula Krogh is incorrect.

In geology, the term variety usually refers to gemstones. For example, aquamarine and emerald are varieties of the mineral beryl; and, citrine, amethyst, ametrine and smoky quartz are varieties of quartz.

Labradorite is an intermediate member of the plagioclase solid solution series. The end-members are albite (sodium tectosilicate) and anorthite (calcium tectosilicate). The intermediate members have varying amounts of Na and Ca usually expressed as a percentage of anorthite. The ternary diagram below shows the compositional differences between the plagioclase feldspars and the alkali feldspars.

For completeness, I will also throw in mineral polymorphs, which have the same chemical composition but have differing crystal lattice structures. For example, sanidine-orthoclase-microcline are polymorphs. They have the same chemical composition. Both sanidine and orthoclase belong to the monoclinic crystal system with sanidine being the high-temperature polymorph and orthoclase being the low-temperature polymorph. The crystal system for microcline is triclinic. Amazonite is a variety of microcline. Another example of polymorphs are kyanite, andalusite and sillimanite.

Labradorite is most often found in mafic igneous rocks (e.g. gabbro).

Woody
Hi ASTROBLEME

I agree it does resemble Labradorite and it would be very interesting to see some come from that area. but at the time I cast my vote against it after I expanded the pic and it appeared to me
the coloration was not sub-surface and it appeared to have the heat cracks commonly associated with melted glass. I thought it lacked depth and iridescents. I do hope you are right. One test
that feller could do is to shine a light in back of the specimen. Labradorite would be fairly opaque while even melted glass should light up considerably. I guess some things you just got to hold
in your hand. It will be interesting to see how it turns out, I'm rooting for you.

Have a good one, Woody.

(5 minutes later).....
Of course after I wrote all this, I now see that other post where it mentions, "flashes Green and Blue". That's what I was looking for!
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