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Post by snowmom on Dec 30, 2014 6:13:37 GMT -5
45th parallel, second and third weeks of December, and we had above freezing weather for almost 14 days. Amazing! I took advantage of that to go back to some of my favorite beaches and listen to the waves which will be silent soon until April or so.. Iced over! I found a few interesting Unakite and Epidote, and a real surprising melt rock, also this mica or tiger eye. ? can you tell me what it is? So long to warm weather, this morning real winter began with a bite. 17 degrees with predicted wind chill to 10 below. Happy New year! May the best of everything come your way in 2015! 
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Post by Peruano on Dec 30, 2014 12:34:59 GMT -5
That 17 degrees almost exactly matches central New Mexico this morning, and yes we will have the wind chill with 50 mph winds predicted. No frozen beaches those - ours are all dry and fossilized. I can't id the rock - you need to buy a trim saw to amuse you this winter. Tom
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Dec 30, 2014 13:36:53 GMT -5
Happy New Year too!
No help with your rock, sorry.
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Post by snowmom on Dec 31, 2014 6:55:15 GMT -5
think I figured it out after about 5 hours on the internet yesterday. Mica "books" stacked in a star formation
(see star mica) and then worn away, you can see how it would have had points if the crystals had remained intact. Some individual crystals are visible even in the photo. it is not flaky like mica, some sort of hardening (silica replacement or infilling?) has taken place at some point. a mineral collector may find a bit of interest in it. Probably wouldn't cut well, who knows if it is as hard inside as out.
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jamesp
Cave Dweller 
Member since October 2012
Posts: 36,612
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Post by jamesp on Dec 31, 2014 9:09:32 GMT -5
HNY Deb. I have seen quartz with those edged faces from thick mica stacks here. Or holes where the mica crystals came out and left the edge marks in the hole.
magnifier is too cool.
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Post by snowmom on Dec 31, 2014 18:16:57 GMT -5
JamesP wish I could picture what you describe, got any photos I could look at? You think this might be quartz? Or am I not understanding (most likely, since I seem to be in a perpetual state of confusion). the crystals I see are the ones you see in the photo, flat and plate like, just as an individual flake of mica, but solid in the rest of the rock, which is also solid. About the middle of the far right a couple are pretty obvious there. Yes, that magnifier helps so much! Thanks!
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,612
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Post by jamesp on Jan 2, 2015 9:23:27 GMT -5
The etching marks look like the sides of mica books. The rock does not look like a typical mica pegmatite, but it can be variable. To get those marks the stone would have had to have been surrounded by mica books. May not be the cause, but a good possibility. I find quartz and felspar with mica scars on it, where the soft mica crystals have weathered away. Atlanta is about all granite=mica + quartz + felspar. Have hounded these boring granite quarries. Boring till you find a perfect black tourmaline crystal 6 inches in diameter and 2 feet long. Or a big beryl or garnet crystal. No matter, you can't chisel it out w/out tearing it up when encased in that granite. Here is sort of a coarse granite- mica books, quartz and felspar  |
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Post by gingerkid on Jan 2, 2015 15:18:29 GMT -5
Happy New Year, snowmom!  Not sure what ya got there, but thought you might enjoy this website. At one time, you could download a pdf of the website. stoneplus.cst.cmich.edu/gemrx.htmThere's a section on conglomerates, and there's one from Michigan called Tillite that looks kinda like the one you are asking about. ?? |
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Post by snowmom on Jan 3, 2015 7:34:33 GMT -5
Tillite is considered by some to be an outdated concept and name these days. I couldn't get this program to open for me, but I believe I have seen it before, might even have it saved somewhere. A search for "gowgonda tillite" will still bring up a lot of pictures, but I don't think it looks much like the second rock pictured here.( your mileage may vary) I believe the second rock shown here to be impact or volcanic melt rock rather than conglomerate/accumulate. Look closely to see the melted effect! Thanks for thinking of me!
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Post by pghram on Jan 5, 2015 21:50:04 GMT -5
Nice finds.
Rich
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Not sure what ya got there, but thought you might enjoy this website. At one time, you could download a pdf of the website. 
