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Brushbuffalo
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PostTue Nov 21, 2017 8:36 am 
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"Could you start a 'name that rock' thread?"

Ask, and you shall receive. [ edit: modified to "What's this rock? What's that landform?"]

Due to several requests, here goes.  Although it sometimes can be very difficult to identify materials from just pictures without a sample in hand, and often also an extended visit to a site and the surroundings,  let's give it a whirl.

Send clear pictures of rocks to this thread if you'd like me to give a shot at identifying for you and our audience.
Ideally, images should be as close-up as you can do, with something in the picture for scale (key, Swiss Army knife, etc.). Also it is helpful to include a photo with a more general view of the outcrop.
- Please try to show "fresh" rock, not stained, excessively weathered, dirty, or lichen-covered surfaces.
- "Bedrock" is still attached, "float" is loose rock. Either is fine.
Please also include if possible:
-Location, being as specific in your description as you can.

My credentials:
Banged with a rock hammer and carried samples as a strapping young USGS field assistant for geologic 'rock stars' ( ouch!  nopity.gif )Rowland Tabor, Dwight Crowder,  and other outstanding geologists in the North Cascades.
B.S. in Geology(1970) Western Washington State College
M.S. in Geology (1977) Western Washington University
43 years teaching college geology, meteorology,  and oceanography
Professor (emeritus), Whatcom Community College, Bellingham. Have had the privilege of working with thousands of students of all ages, including a freshman grandchild of one of my early students. smile.gif How time flies.
I've seen not only a lot of rocks but also structures and landforms in the Cascades and elsewhere! biggrin.gif  You can ask questions about those things, too, without fear of the dreaded hijacked.gif !
I especially like weird oddities. Sometimes they are simple to explain, but once in a while.... confused.gif !
Keeps the ol' gray matter alive... hihi.gif
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contour5
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PostTue Nov 21, 2017 11:29 am 
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I'm curious about these crystals I found.
Crystals-1
Crystals-1
Crystals-2
Crystals-2

They were exposed on the uphill side of a 3' boulder in the talus apron at the base of Alta Mtn. (right below the lens flare in this picture)

Here's some bedrock peeking out a couple hundred feet above the tarn:

There were also boulders of conglomerate laying around:
Conglomerate
Conglomerate

I didn't get a good shot of the crystal boulder, but you can see some of it here:
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DIYSteve
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PostTue Nov 21, 2017 11:41 am 
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Cool. Very gneiss of you  wink.gif
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Brushbuffalo
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PostTue Nov 21, 2017 11:50 am 
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Thanks for getting this started, contour 5! You included lots of good images, including close-ups. Perfect!
Crystals-1 is quartz (#2 in continental crustal abundance)  with feldspar (#1) in upper right and in left 1/3 of image.
Crystals-2 is all quartz, and  good euhedral (good external form) crystals!
The 'conglomerate' is breccia as indicated by the angular nature of the particles. I'm calling it volcanic breccia rather than sedimentary breccia.
On the geologic map of the North Cascade Range, Alta Mountain is mapped as "Tcao",
which is "volcanic and sedimentary rocks of Ohanapecosh episode ( Oligocene). Remnants of a series of volcanoes that erupted from about 34 to 30 million years ago."

(and Steve, thanks for the gneiss comment)

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Kim Brown
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PostTue Nov 21, 2017 11:53 am 
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Be still, my heart! Yer talkin' purty.  wub.gif

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" I'm really happy about this! … I have very strong good and horrible memories up there."  – oldgranola, NWH’s outdoors advocate.
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Malachai Constant
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PostTue Nov 21, 2017 11:54 am 
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Quartz crystals, the rock is breccia as the fragments are sharp cornered conglomerates are usually rounded cobbles cemented together.

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"You do not laugh when you look at the mountains, or when you look at the sea." Lafcadio Hearn
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radka
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PostTue Nov 21, 2017 1:08 pm 
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Brushbuffalo
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PostTue Nov 21, 2017 1:21 pm 
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edited
Greenish quartz is uncommon and some isn't even naturally- occurring.  The partially fake kind  is called aqua aura quartz and interestingly, the color is due to traces of gold.  Pretty stuff, even if slightly faux. But the gold in it is not concentrated as pure gold such as gold nuggets in vein quartz. Aqua aura quartz has a cultish aspect.. In fact, it is not a natural color!

So what you saw on Blackcap might be  prasiolite. I've neither seen it nor heard of it in the Cascades, but that means very little per se. Not even Rowland Tabor has seen all the rocks, or even Fred B, Fay, or John R!

Edited again on Nov. 24: green mineral is most likely fluorite. Thanks, GC99.  smile.gif

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Kim Brown
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PostTue Nov 21, 2017 1:57 pm 
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radka wrote:
I found this gem at the saddle of Blackcap in the Pasayten last year. I carried it to the summit and put it on the top of the summit cairn - it may still be there

That'll baffle geologists hundreds of years from now. embarassedlaugh.gif

I used to collect pretty rocks and stones; I had 'em in vases and on my windowsill.

But then I learned that a rocks job on earth is to make it to the nearest trench, where it can morph and become another rock.  So I felt sorry for the rocks and stones and I had been holding in captivity. So I released them all into the Whitechuck River. I pity the geologist who finds them - the poor bastard will spend a lifetime trying to solve the puzzle of the obsidian, serpentine, and a rock with a horsey painted on it that he found there. Then the archeologists will get in on that; they'll pull them of the site where they are excavating the giant leaf fossils that found embedded in a road structure in Issaquah.

So now when I walk along the beach on the Pacific Coast, I like to pick up rocks and stones and throw them back into the surf.

And I really feel sorry for decorative rocks stuck in gardens and imbedded in cement stairs and walls. And it’s one reason I don’t do trail work anymore. I couldn’t stand pulling a nice rock that had a perfectly sound plan for getting into the trench – only to be picked up and plunked into a spot on a rock retaining wall. I kept weeping and creating more mud, which meant more and bigger rocks were needed; that didn’t help. So I had to quit.

Don’t get me started on highways and sidewalks.

Pappa was a rolling stone!
I am a rock, I am an island!
I turn to stone!
Everybody must get stoned!

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" I'm really happy about this! … I have very strong good and horrible memories up there."  – oldgranola, NWH’s outdoors advocate.
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Brushbuffalo
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PostTue Nov 21, 2017 2:03 pm 
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Kim Brown wrote:
a rocks job on earth is to make it to the nearest trench, where it can morph and become another rock.

"Everything either is now or is becoming a rock". Don't know who to attribute that witticism to.... clown.gif

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Kim Brown
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PostTue Nov 21, 2017 2:06 pm 
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Sorta like the tide is coming in.  Or going out.

So yeah, great thread. I have a mystery rock (that I did keep - it's that cool) I'll post a portrait of it tonight!

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Jake Robinson
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PostTue Nov 21, 2017 3:25 pm 
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Not really a rock ID question, but any idea how these parallel lines could have formed? This was taken on the summit of Mount Mystery in the Olympics.

Mystery rock feature
Mystery rock feature
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Hesman
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PostTue Nov 21, 2017 3:52 pm 
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Found in the Olympic Mountains near Surprise Basin between Royal Lake and The Needles. It is a dark green color.

PS...Should I post a pic of my agate collection? It is has almost 22,000 agates in it. hockeygrin.gif  winksmile.gif  I know I'ma bit crazy.gif about finding them.

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moonspots
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PostTue Nov 21, 2017 5:46 pm 
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Brushbuffalo wrote:
"Could you start a 'name that rock' thread?"

Ask, and you shall receive.

Due to a several requests, here goes.  Sometimes it is very difficult to identify materials from pictures, but let's give it a whirl.

Oh, I think that's a great idea.


I found some rocks in a creek bed in the area of Capital Forest several years ago that I've not been able to identify. Now, if/when I find 'em again in all my "stuff", I'll send along a pic and a request for your best guess.

But for now, I'll describe what I thought was different and interesting. When I broke them apart (easily done), I found small spherical voids (maybe about 1/8" in diameter) inside that were coated with either a white or light blue substance. Not quite crystaline, but not smooth either.

Now, time for me to go start looking....

And thanks for starting an interesting thread.




And, now I found my mystery rock this morning:

rock from capitol forest
rock from capitol forest

It's about 1 1/2" square for a size reference. Notice the small cavities with a slight blue tint (bottom center of rock image)? They were quite a bit brighter (but still a pale blue) when I first cracked it open maybe 6-7 years ago. I found only a very few of these in a creekbed in the hills maybe 15-20 miles west of Olympia.

Any ideas?

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Brushbuffalo
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PostTue Nov 21, 2017 5:50 pm 
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Jake Robinson wrote:
any idea how these parallel lines could have formed?

Jake, Mount Mystery is basalt. Without being there or seeing more photos my educated guess is those are small, very uniform contraction columns in a deformed bed such that the columns are lying with their long axis horizontal. Typically when columns form in a lava flow they are remarkably uniform in size....from all tiny (like these, if indeed that's what they are) to huge, like in the Roza basalt flow popular with climbers at Frenchman Coulee.

That's one exposure I would love to see up close and personally.  I was with Tabor and Crowder in 1967 near there when we ( they, really. I knew very little, I was just the mule  biggrin.gif ) encountered the first pillow basalt known in the northeast part of the Olympics. Pillow basalt, erupted under water, is quite common in the Olympics. Mini- contraction columns, not so much. Columns just a few centimeters in diameter are not unknown.  There are larger columns visible along US-101 down by Hood Canal in places.

It is interesting that in the Olympic basalts there are fine examples of both pillows and contraction columns. According to researchers this indicates the assemblage of basalt flows was so thick that even being submarine in origin, some areas were evidently islands, enabling some  flows to form subaerially and develop contraction columns.


Maybe whoever named that mountain saw your rock outcrop...."mystery"  confused.gif

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