Forum Index > Trail Talk > "What's this rock? What's that landform?"
Previous :: Next Topic  
Author Message
Brushbuffalo
Member
Member


Joined: 17 Sep 2015
Posts: 1207 | TRs
Location: there earlier, here now, somewhere later... Bellingham in between
Brushbuffalo
  Top

Member
PostWed Nov 22, 2017 6:29 pm 
Reply to topic Reply with quote
Jake and Adam,
Good scale, a bit out of focus.. edit actually  perfectly sharp focus. My initial view was with my tablet being weird dizzy.gif

From the fragments I see, these are some kind of bivalve, such as a clam or brachiopod.
Unfortunately, I'm a poor paleontologist. A good one would give you the genus and species.

Rock is almost certainly limestone.

--------------
Passing rocks and trees like they were standing still
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
Gimpilator
Member
Member


Joined: 12 Oct 2006
Posts: 1293 | TRs
Location: Edmonds, WA
Gimpilator
  Top

Member
PostWed Nov 22, 2017 9:14 pm 
Reply to topic Reply with quote
Thanks Doug.  Jake told me there was a rock topic going on.  What a fun idea!  I asked him to post for me because I'm without a real computer for awhile and can't do much with this darn phone.

--------------
http://www.summitpost.org/user_page.php?user_id=25744
http://www.peakbagger.com/climber/ClimbListC.aspx?cid=2650&sort=elevft&u=ft&j=-1&y=9999

Keep climbing mountains and don't slip!
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
HitTheTrail
Member
Member


Joined: 30 Oct 2007
Posts: 4880 | TRs
Location: Rescuing Shackleton
HitTheTrail
  Top

Member
PostThu Nov 23, 2017 9:58 am 
Reply to topic Reply with quote
Great idea! up.gif
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
GC99
Member
Member


Joined: 25 Jun 2015
Posts: 24 | TRs

GC99
  Top

Member
PostThu Nov 23, 2017 10:21 pm 
Reply to topic Reply with quote
radka wrote:
Oh, I have one for you!

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.


Radka,

That greenish rock you posted looks to be Fluorite. It is present in the quartz porphyry dikes of the area. There were even some claims staked on Monument Peak years ago to mine the stuff, but nothing ever came of it. These small deposits are all over that area, with some many prominent ones on Dot Mountain. Great find!
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
Brushbuffalo
Member
Member


Joined: 17 Sep 2015
Posts: 1207 | TRs
Location: there earlier, here now, somewhere later... Bellingham in between
Brushbuffalo
  Top

Member
PostFri Nov 24, 2017 6:57 am 
Reply to topic Reply with quote
GC99 wrote:
Fluorite

Good identification, GC99, and I'm buying it.  Fluorite is not a particularly common mineral in these parts but superficially resembles quartz. The greenish color should have tipped me off.   I was hasty in hypothesizing it was aqua aura quartz ( highly improbable) or prasiolite (rare, and so far as I know, not found in the North Cascades).  This is an example where examining from pictures can lead to strange guesses. In the hand, fluorite ( hardness of 4)  will easily be scratched with a knife, but quartz (h=7) will not scratch.

GC99 and others : Please help with identifying the oddities that are bound to be coming in. We appreciate expertise.

--------------
Passing rocks and trees like they were standing still
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
Brushbuffalo
Member
Member


Joined: 17 Sep 2015
Posts: 1207 | TRs
Location: there earlier, here now, somewhere later... Bellingham in between
Brushbuffalo
  Top

Member
PostFri Nov 24, 2017 8:23 am 
Reply to topic Reply with quote
moonspots wrote:
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.

I'm calling the rock a basalt porphyry ( dark groundmass with macroscopic but still small crystals...the tiny, barely visible light specks, not the obvious large whitish objects ).
This basalt is from the Crescent basalt formation, which is widespread on the Olympic Peninsula.

The cavities are vesicles ( very common in basalt). I can't tell from the pictures for certain, but the white minerals  could be quartz, calcite, or a zeolite. Let's say they are quartz. Quartz does not occur as a primary mineral in basalt but after a flow cools and sits there for umpteen millenia, silica-saturated fluid can penetrate the basalt, find its way into the vesicles, and crystallize. The largest partially filled vesicle in your picture shows particularly well-formed ( euhedral) crystals. These form because they are not competing for space with each other within the vesicle as growth occurs. Filled or partially filled vesicles make this an amygdaloidal basalt ( there's a good term to mention...casually as possible....at your Christmas party).
I'm less certain about the bluish tint, however.  It seems to be more on the basalt surface and may be due to microscopic ferromagnesian minerals such as pyroxene. The illumination might be ptoducing an effect, too. Note the difference between the "bluish" left face and the dark gray upper flat face.

--------------
Passing rocks and trees like they were standing still
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
RichP
Member
Member


Joined: 13 Jul 2006
Posts: 4357 | TRs
Location: Moscow, Id.
RichP
  Top

Member
PostFri Nov 24, 2017 8:27 am 
Reply to topic Reply with quote
Here's my contribution. Found in the Chopaka Mtn area.


These rocks tell a story.
These rocks tell a story.

--------------
Without obsession, life is nothing. John Waters
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
Brushbuffalo
Member
Member


Joined: 17 Sep 2015
Posts: 1207 | TRs
Location: there earlier, here now, somewhere later... Bellingham in between
Brushbuffalo
  Top

Member
PostFri Nov 24, 2017 8:34 am 
Reply to topic Reply with quote
RichP,  yours appears to be a spectacular example of sedimentary breccia. The prominent banded clast in center is gneiss, derived from bedrock gneiss somewhere in the vicinity when the sediments forming the breccia were deposited.
A very poorly sorted breccia comprised of very angular particles  indicates rapid deposition and a short transport distance, such as a landslide.

Edit: Once again, jumping to a premature conclusion.  I see on my larger monitor that there is an angular block of gneiss that is  merely resting on top of the brownish rock. I originally thought this and the other  blocks were part of the larger rock, hence my comments about rapid deposition forming a very poorly-sorted breccia.

I am not familiar with the specific geology of the Chopaka area. The brown rock may be tuff breccia, a volcanic material made of subangular and angular macroscopic particles held within a finer-grained matrix of ash.  The larger fragments are largely  crystalline and phaneritic (coarse grained), indicating a plutonic source before being fragmented and lithified as a volcaniclastic rock.
Phew! Lots of terminology there.  And I may be all wet! One thing's for sure...fascinating rock!

--------------
Passing rocks and trees like they were standing still
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
daffish
Member
Member


Joined: 16 Sep 2009
Posts: 269 | TRs
Location: Dreamtime
daffish
  Top

Member
PostFri Nov 24, 2017 10:55 am 
Reply to topic Reply with quote
Crystal Formations on brown rock
Crystal Formations on brown rock
Crystal Formations #1
Crystal Formations #1
Crystal Formation #2
Crystal Formation #2
crystals were in the talus and boulders in the immediate foreground
crystals were in the talus and boulders in the immediate foreground
Small example
Small example
small rock example
small rock example

I have always been curious as to what this formation is. From the first picture, I thought it was a type of fossil, but I am not so sure now.

These were found in the basin west of Silvertip Peak in the Monte Cristo area. They appeared mostly on the edges of the boulders and talus in one small area with the rays of the formations about 1" - 2.5" long. On the smaller rock which I brought home, the rays are quite short and not as pronounced.

--------------
"Be moderate in everything, including moderation"     Horace Porter
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
Brushbuffalo
Member
Member


Joined: 17 Sep 2015
Posts: 1207 | TRs
Location: there earlier, here now, somewhere later... Bellingham in between
Brushbuffalo
  Top

Member
PostFri Nov 24, 2017 1:14 pm 
Reply to topic Reply with quote
daffish wrote:
Crystal Formations on brown rock
Crystal Formations on brown rock

I believe that this is a remnant of a  vein that filled a fracture in the brown rock. The rock broke along the fracture, being a plane of weakness, and some of the vein mineral remained on this piece that you photographed.
Sorry, but without having the sample  in hand to check things such as hardness and angle between cleavage  planes, etc., I won't venture a guess as to the specific mineral identity of your other pictures.

Actually I will, but it's just a guess.There may be  minerals in the heavily mineralized Monte Cristo area that I might not be familiar with. However, the long prismatic crystals in the prominent whitish mineral suggest it may be a member of the amphibole family.  The fanlike habit of the crystals is interesting.

--------------
Passing rocks and trees like they were standing still
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
moonspots
Happy Curmudgeon



Joined: 03 Feb 2007
Posts: 1907 | TRs
Location: North Dakota
moonspots
  Top

Happy Curmudgeon
PostFri Nov 24, 2017 1:27 pm 
Reply to topic Reply with quote
Brushbuffalo wrote:
I'm less certain about the bluish tint, however.  It seems to be more on the basalt surface and may be due to microscopic ferromagnesian minerals such as pyroxene.

The little pockets of "bluish tint" are not on the surface until the small shperical voids were broken open, but the blue was a brighter, (yet pale) color when the rock was newly cracked open.  I wish I knew enough about rocks and minerals to have an idea as to what they might be. Maybe at Christmas I can get me son to take me back to where I found this and perhaps find another.

Thank you (and all others) for offering opinions.

--------------
"Out, OUT you demons of Stupidity"! - St Dogbert, patron Saint of Technology
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
Byeguys
Armchairing



Joined: 09 Feb 2006
Posts: 1411 | TRs
Location: Sparkwood & 21
Byeguys
  Top

Armchairing
PostMon Nov 27, 2017 9:56 am 
Reply to topic Reply with quote
Brushbuffalo wrote:
moonspots wrote:
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.

I'm calling the rock a basalt porphyry ( dark groundmass with macroscopic but still small crystals...the tiny, barely visible light specks, not the obvious large whitish objects ).
This basalt is from the Crescent basalt formation, which is widespread on the Olympic Peninsula.

Analcime was my first guess on this one as well, makes sense (but can't confirm from here) given the crystal shape/color, vesicle distribution/shape/fill, and location of discovery.

daffish wrote:
Crystal Formations #1
Crystal Formations #1
Crystal Formation #2
Crystal Formation #2

These remind me of muscovite, I suppose you can find it around Monte Cristo but I really think my guess is way off. Does the piece you brought home feel heavier than it should, as if it had metal/ore content?
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
Byeguys
Armchairing



Joined: 09 Feb 2006
Posts: 1411 | TRs
Location: Sparkwood & 21
Byeguys
  Top

Armchairing
PostMon Nov 27, 2017 10:03 am 
Reply to topic Reply with quote
moonspots wrote:
The little pockets of "bluish tint" are not on the surface until the small shperical voids were broken open, but the blue was a brighter, (yet pale) color when the rock was newly cracked open.  I wish I knew enough about rocks and minerals to have an idea as to what they might be. Maybe at Christmas I can get me son to take me back to where I found this and perhaps find another.

Thank you (and all others) for offering opinions.

Go driving around Pe Ell and look for quarries on the logging roads. Should find ****loads of these little guys with a day or two of patience. Probably start finding a few natrolite sprays and some larger pockets with persistence.

Edit: road fill seems to usually come from a nearby location on those roads, get out and check for material now and then. Spot good stuff in the road bed? Start keeping an extra eye out for the cut/quarry. Can make for some fun scavenge-hunt-ish days.
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
Brushbuffalo
Member
Member


Joined: 17 Sep 2015
Posts: 1207 | TRs
Location: there earlier, here now, somewhere later... Bellingham in between
Brushbuffalo
  Top

Member
PostMon Nov 27, 2017 11:29 am 
Reply to topic Reply with quote
Doppelganger wrote:
Analcime was my first guess on this one as well

Analcime https://en.m.wikipedia.org/wiki/Analcime is generally considered to be a member of the zeolite family. It is a strong candidate for a mineral in the amygdales (filled vesicles) in the picture.  Doppelganger and I would love to examine it in the hand, or better yet in thin section.

I also thought of muscovite for the fan-shaped  minerals, but I can't confirm just from the images.  Muscovite forms thin transparent elastic sheets that split very easily.
Large sheets of muscovite were used for the window in ancient parlor stoves, as well as in old candle lanterns. I think I still have my antique muscovite candle lantern.  smile.gif

--------------
Passing rocks and trees like they were standing still
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
pcg
Member
Member


Joined: 09 Jun 2012
Posts: 225 | TRs

pcg
  Top

Member
PostFri Dec 22, 2017 12:01 pm 
Reply to topic Reply with quote
This stuff is scattered around the top of Pueblo Mountain, in Oregon just north of the Nevada border. The rock is 4" across.

Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
  Display:     All times are GMT - 8 Hours
Forum Index > Trail Talk > "What's this rock? What's that landform?"
  Happy Birthday Flash Gordon, raz2sea!
Jump to:   
Search this topic:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
   Use Disclaimer Powered by phpBB Privacy Policy