Name that rock

I was looking at some old rocks and found this one with kind of a gray bubble surface on top and was just wondering what it might be. It's kind of hard to make it out so I'm posting some other rock with kind of the same bubble appearance in quartz I guess.










[Edited on 24-1-2014 by Morgan]

A psilomelane?


Romanechite:


hollandite:


Where dit it come from?

My father is a geologist and has a large collection of rare rocks, can anyone guess what these are?

Quote: Originally posted by Pinkhippo11

My father is a geologist and has a large collection of rare rocks, can anyone guess what these are?

On the topic of botryoidal formations, here are a couple from my collection.

Hemimorphite (blue), Malachite/Azurite (green/royal blue)

hyalite opal .......................................fire agate


jade................................................... lepidolite in front of a lamp



the hyalite opal flouresces but the camera I was using sucks, so it didn't show any of the color. UV won out it is about 1/10th the brightness of uranium glass I have( good stuff, quite bright)

Quote: Originally posted by Random

Guys how do you identify rocks? Is there some kind of protocol for that? I never understood how one could do it so easily if there are so many similar ones and each rock actually looks even more similar to my untrained eye.

This rock looks like it fractured, shifted, and then cemented itself back together. I don't know what formed it that way or what it's called. Or maybe it grew and crowded into this arrangement?



[Edited on 26-1-2014 by Morgan]

This is some crumbly rock I have no idea about.

More of my inherited outdoor rocks, I made a sharp flat shard in a shiny solid black obsidian that fits in the palm of my hand. The very thin cutting edge is translucent brown if held up to the light while the rest opaque glassy black. I just took a hunk and hit it with a hammer. It's neat how you can fit the strange smooth surfaces back together if you split one in half.
I like these other obsidian pieces better though, the few pinkish speckles here and there might be pretty if the piece were split open. The other kind of reminds me of a wood grain.
I find the shapes of rocks almost as interesting as what they are made of sometimes.

Quote: Originally posted by elementcollector1

Looks like paint on the outside to me...

Some purple rocks.

Some kind of green rock. I don't know what it is.




[Edited on 27-1-2014 by Morgan]

Some curvy things. They're quite heavy. You can see a porousness to them.

Kind of a clay sandstone material?

I'm not sure what to call this. It appears to be a fine clay-like layering but hard now with a slight ring to it if you tap the thin pieces.

I wonder where this stuff comes from? You see it all over as round polished gift shop stuff. Still it's kind of nice. I would like to explore the Burgess Shale Formation I think.

Looks like petrified wood. They're very heavy.




[Edited on 27-1-2014 by Morgan]

Quote: Originally posted by Morgan

Some kind of green rock. I don't know what it is. [Edited on 27-1-2014 by Morgan]

More of my outdoor rocks, a hodgepodge of commoners I suppose. The tiger eye dabbed with a little water for picture day. I don't know the names of the picture 48 group or what they may be.

This is a simple little rock or mineral but not much in the way of clues other than if you wet it, you can sort of see into it somewhat, or not opaque if you polished it. But it's a very dark green, that's about it. It would be glassy if polished, no grains in it.

Quote: Originally posted by Morgan

This is a simple little rock or mineral but not much in the way of clues other than if you wet it, you can sort of see into it somewhat, or not opaque if you polished it. But it's a very dark green, that's about it. It would be glassy if polished, no grains in it.

I wonder what causes this crinkle effect, as if the surfaces were melted and pressed against something?

[Edited on 27-1-2014 by Morgan]

A smooth rock of some sort.

The camera didn't capture the sheen this slate-like rock had. It also had more of a green tint. I couldn't get the angle right in the sunlight.

Here is a cool metamorphic rock studded with garnet porphyroblasts that I found up at my cottage during the summer. I'm not exactly sure whether the host rock would be classed as a gneiss or a granulite, although I think that it seems more like a granulite.

Here are a few really cool features that I found up at my friend's place near Parry Sound during the summer.

The first image is of a highly metamorphosed, folded, mafic dike (amphibolite) that cuts through some sort of felsic granulite.

The second image, from the same area, shows at least four different geological processes: (this is my opinion)

1. The creation of the felsic granulite
2. The intrusion of a mafic dike, presumably diabase or gabbro at that point in time (middle left to top right)
3. The metamorphosis of said dike into amphibolite
4. Finally, the relatively more recent intrusion of a pegmatite dyke (across the center)

The third image is another example of the second (the wide amphibolite dike curves from bottom right to top left; the pegmatite dike cuts across the center dipping slightly to the left)

Quote: Originally posted by Morgan

I wonder what causes this crinkle effect, as if the surfaces were melted and pressed against something? [Edited on 27-1-2014 by Morgan]

Left one might be Amber? If so that's a nice big natural chunk of it!

I think Oregon is a good bet for the source of most of these. I had a friend that carted home an essentially identical collection to yours while hiking around south-central WA. I helped him clean & organize them later.

Cleaning sometimes involved a fun trick I found online somewhere:
1: Drop your specimen(s) into an HCl bath
2: Tear a sheet of aluminum foil into strips
3: Add foil strips to HCl bath. Observe vigorous redox rxn.
4: Fish out your specimens & observe what remains

Was pretty interesting to see what survived. Worked great for cleaning dirt or rock off of crystal formations. But sometimes destroyed the whole specimen

Quote: Originally posted by Morgan

I was thinking it was garnet too remembering another rock I have and a previous post of yours of a rock face loaded with them.

bfessor I must have spaced out thinking you posted some previous garnet pictures. The amber looking rock is too heavy to be amber but the crinkle effect and color does look like it.
I was looking at/enlarging the photo of the big, smooth, slate blue rock again and the curved lines around the ends almost make it look like a petrified wood.

Some other rocks, last of the pile. And so concludes this collection of misfit rocks, rocks that weren't showy enough to be indoors. Individually each one didn't have much appeal to me, but now that I look at them collectively, they do.

Thanks again to all for all the interesting comments.




[Edited on 30-1-2014 by Morgan]

Again, the first one looks like chalcedony. The ones in the sixth photo appear to be river-worn granite <a href="https://en.wikipedia.org/wiki/Particle_size_(grain_size)" target="_blank">cobbles and pebbles</a> <img src="../scipics/_wiki.png" />. Are strong magnets attracted to any of the others?

If it's alright, I'd like to keep this topic going as a sort of 'geology pretty pictures' thread. Here is a composite photo I made of the bend in the St. Croix river through <a href="https://en.wikipedia.org/wiki/Interstate_Park" target="_blank">Interstate Park</a> <img src="../scipics/_wiki.png" />&mdash;the view is from 'Angle Rock' on the inside (MN) of the sharp bend caused by the river eroding down through a fault in the basalt (<a href="http://aerialgeologist.blogspot.com/2013_07_01_archive.html" target="_blank">ref.</a> <img src="../scipics/_ext.png" />:

<a href="http://www.flickr.com/photos/35937732@N02/11988098314/" title="St. Croix River, Interstate Park, MN by bfesser, on Flickr" target="_blank"><img src="http://farm6.staticflickr.com/5530/11988098314_a41ff2a934_c.jpg" width="800" height="176" alt="St. Croix River, Interstate Park, MN"></a> <img src="../scipics/_ext.png" valign="top" />

(Yes, I'm aware of the slight compositing error in the trees near the right of the photo. I was unable to correct it.)

Attachment: interstate_geology.pdf (716kB)
This file has been downloaded 1031 times

[Edited on 30.1.14 by bfesser]

Quote: Originally posted by Morgan

Some other rocks, last of the pile. And so concludes this collection of misfit rocks, rocks that weren't showy enough to be indoors. Individually each one didn't have much appeal to me, but now that I look at them collectively, they do. Thanks again to all for all the interesting comments. [Edited on 30-1-2014 by Morgan]

Am still thinkin' its amber...A chunk of natural amber that size wouldn't feel too much different from a rock of the same size. It can be surprisingly heavy. The appearance is spot on too: it usually looks kinda like lava, forming globs & puddles as it flows...but also gets the crinkled effect from all the pine needles and other crud that it encounters from being so damned sticky all the time. hehhe...
I opened the picture in a pic editor and tried to mess around with the brightness/contrast/colors/etc a little bit, attached below. May have gone a smidge too far into the 'reds'. Whatever the case, its a very cool piece. I'd love to see more pics from different angles at some point - am interested in the slightly darker 'bulbs' on right&left corners, and maybe back corner too? It's too hard to say for sure from the one pic...



My first thought was mica or vermiculite for the flaky stuff too. It does look pretty identical to muscovite I've seen before but the placement/occurence of it in that speciment are way more consistent with mica I've seen (in my very limited experience).

I'm glad you expanded the thread bfesser! Now I have excuse to dig out all sorts of goodies! I've got a few Aquamarines with cool looking muscovite all over them that would pertain to this particular discussion. Those will be first, & then maybe a ton of natural pyrite samples I've got in a cigar box somewhere a bit later.

Quote: Originally posted by Pathos

My first thought was mica or vermiculite for the flaky stuff too. It does look pretty identical to muscovite I've seen before but the placement/occurence of it in that speciment are way more consistent with mica I've seen (in my very limited experience).

Quote: Originally posted by Pinkhippo11

Could the one with orange stripes be banded iron?

Quote: Originally posted by bfesser

I tried taking photos of some of my mica schist specimens a few days ago, but my camera battery died before I got up to the good specimens from the <a href="http://www.mindat.org/loc-22519.html" target="_blank">Black Hills, SD</a> <img src="../scipics/_ext.png" />.

Quote: Originally posted by chemrox

I just started looking at these. The first were the mineral fluorite... good examples too... typical colors are white, violet-purple and green. The purple kind is easily confused with amethyst until you scratch it.

The amber colored crinkle rock is about as hard as quartz I would say and certainly not a 2-3. I heated an edge and it changed to a darker orange and a tiny flaky shard popped off. I hit the rock with the wire wheel side of my grinder and then the grinding stone side and it's hard. Still I don't have a name for it.





[Edited on 2-2-2014 by Morgan]

bfesser here's that one rock I tried to magnify for you with meager results. With my eyes it seems like one or two flecks are red but the camera doesn't really show it.

This rock is really glittery in strong sunlight and it leaves glitter on your fingers too.

Quote: Originally posted by Morgan

Still I don't have a name for it.

Neodymium magnets will stick to this, better in some spots if I recall. It has a more glittery appearance and slightly greener if viewed directly instead of the camera.

I think I found the source of that piece of white crinkle rock but not the name.

I was wondering what the green is?

Quote: Originally posted by Morgan

This is some crumbly rock I have no idea about.

This one reminds me of fine clay sort of.

I split some black obsidian . The pieces almost look like black tar, how smooth they are when fractured.

Here's a quartz-like rock which is slightly translucent on the outer surface that seems kind of geode or vug in nature. It's really heavy so probably not hollow. Maybe it would be more telling if it were cracked or sawed open.

Ah, I see the orange one ended up being agate. The extra pics/angles were definitely helpful. Latest crinkly pics are rad - nice rock! Same goes for that biotite garnet schist specimen. Be careful with that one if its very soft because those garnets could just fall out & would be tragic to lose them.

These are a couple days later than I had originally anticipated - but here's those Aquamarine w/ Muscovite pics I mentioned previously, along with a couple Fluorites just for fun

Aquamarines:



Fluorites:


Sorry about the lighting ...I was pretty stoked to see how well the "phantoms" and bevelled edges showed up in the first fluorite pic. That's probably one of my fav crystals. It was *flawless* the day I got it - and later that same day I was doing some homework and put it on the base of my lamp so I could get a better look at it. Needless to say I somehow knocked it off, and it fell a distance of 1 inch onto the desk below. That's what caused the noticeable 'ding' just to the left of the bottom-point in the diamond-oriented cube...so weak...

[Edited on 2-3-2014 by Pathos]

Might as well post these while I'm at it...
1. Smokey Quartz
2. Rose Quartz
3. White Tourmaline with what looks like black tourmaline - but its actually the smallest "Watermelon tourmaline" I've ever seen! lol

4&5. Name that rock? Heh...I found these digging through my collection and can't remember for the life of me what they're called. Eventually I can ask the friend I got them from and he'll remember, but figured I'd post here first. Any guesses?

On the topic of beryl, here is an emerald vein in a biotite schist.

Also, I have this bought specimen that is labeled Magnetite /w Matrix (which seems to be a schist or phyllite). However, the octahedral crystals show no response to any magnet and do not deflect a compass needle. I have always thought that magnetite was magnetic... Any thoughts?

Some common rocks and ordinary unloved rocks with different patterns in them ... I like the one on the end of the top row for the tiny root-like features. You can see them better if you enlarge the photo.




[Edited on 3-2-2014 by Morgan]

Bear with me, I've more.

Blessedly the last.

Coloration in minerals isn't always caused by the presence of transition metal ions. Colors can also arise from the optical effects (diffraction) of physical structures within the specimen (pseudochromatic) and a certain type of crystallographic defect called an <a href="https://en.wikipedia.org/wiki/F-Center" target="_blank">F-Center</a> <img src="../scipics/_wiki.png" />, which are created by naturally occurring ionizing radiation&mdash;as hinted at in your quote. Of course, man has taken advantage of this phenomena to produce artificially colored gems, which are sometimes misleadingly sold as natural specimens.

See also:
<a href="http://www.minsocam.org/msa/collectors_corner/arc/color.htm" target="_blank">The Origins of Color in Minerals</a> <img src="../scipics/_ext.png" /> (American Mineralogist)
<a href="http://minerals.gps.caltech.edu/color_causes/" target="_blank">The Colors of Minerals</a> <img src="../scipics/_ext.png" /> (Caltech)
<a href="http://www.minsocam.org/msa/collectors_corner/arc/colorradiation.htm" target="_blank">The Coloring and Thermophosphorescence Produced in Transparent Minerals and Gems by Radium Radiation</a> <img src="../scipics/_ext.png" /> (American Mineralogist)
<a href="http://www.enmu.edu/services/museums/miles-mineral/colors.shtml" target="_blank">Colors in Minerals</a> <img src="../scipics/_ext.png" /> (Eastern New Mexico University)

On a related note; there has been a huge influx artificial 'mineral specimens' on the market which are originating from China and Poland&mdash;surely other countries, as well&mdash;at the moment, so just be mindful of this if you're purchasing specimens off eBay and the like. Some of the minerals are artificially colored by exposure to ionizing radiation, heat treatment, or similar means. Some of the specimens (CuSO₄ and Bi, in particular) are just lab grown fakes. And some specimens are even glued together from unrelated minerals. Some of the sellers advertise this plainly (e.g. <a href="http://www.ebay.com/itm/131104787298" target="_blank">"Chalcanthite - Lab Grown in Poland"</a> <img src="../scipics/_ext.png" />, others hide the truth in fine print; some are ambiguous (e.g. <a href="http://www.ebay.com/itm/331120436704" target="_blank">"DINO: RAINBOW BISMUTH Crystal Mineral Specimen - 33 gr. Germany"</a> <img src="../scipics/_wiki.png" />, and a few just lie outright.

See also:
<a href="http://www.the-vug.com/vug/vugfakes.html" target="_blank">Fake Crystals, Minerals, Gemstones, Lapidary and Fossils Guide</a> <img src="../scipics/_ext.png" /> (The-Vug.com)
<a href="http://www.fakeminerals.com/" target="_blank">FakeMinerals.com/</a> <img src="../scipics/_ext.png" />

[note: I recently watched a recording of an interesting lecture on this topic (F-centers), but it was on a DVD that I don't own. I'll try to find a copy to share. I also had a couple papers and a book to share, but I'll likewise have to retrieve them. I will be editing this post, as usual; so please don't quote it.]

[Edited on 8.2.14 by bfesser]

I was looking in a few boxes for my purple fluorite crystals and came across these rocks in boxes. The first one didn't photograph well, it's exceedingly glittery but not for the camera. It's a magic rock, completely jet black in indoor light.

More box rocks.

The last of these.

Quote: Originally posted by blargish

Also, I have this bought specimen that is labeled Magnetite /w Matrix (which seems to be a schist or phyllite). However, the octahedral crystals show no response to any magnet and do not deflect a compass needle. I have always thought that magnetite was magnetic... Any thoughts?

Quote: Originally posted by Morgan

The dendritic manganese in Wiki looks like a piece of artwork. I like that effect.

It is a beautiful effect. Here are a few specimens in my collection:

<table><tr><td><a href="http://www.flickr.com/photos/35937732@N02/12414327015/" title="Manganese Dendrites by bfesser, on Flickr" target="_blank"><img src="http://farm4.staticflickr.com/3795/12414327015_ac24eab6db_m.jpg" width="240" height="180" alt="Manganese Dendrites"></a></td><td><a href="http://www.flickr.com/photos/35937732@N02/12414841504/" title="Dolostone by bfesser, on Flickr" target="_blank"><img src="http://farm8.staticflickr.com/7295/12414841504_73afac3070_m.jpg" width="240" height="180" alt="Dolostone"></a></td><td><a href="http://www.flickr.com/photos/35937732@N02/12414390095/" title="Unknown Rock with Mn Dendrites by bfesser, on Flickr" target="_blank"><img src="http://farm3.staticflickr.com/2893/12414390095_2fe81da9b7_m.jpg" width="240" height="180" alt="Unknown Rock with Mn Dendrites"></a></td></tr><tr><td align="center">on Bavarian Limestone</td><td align="center">on Dolostone from WY</td><td align="center">In another WY rock</td></tr></table>
There have been a couple mentions of <a href="https://en.wikipedia.org/wiki/Jade" target="_blank">'jade'</a> <img src="../scipics/_wiki.png" /> in this thread, so here are some specimens I collected in the Bighorn Mts., Wyoming:

<table><tr><td><a href="http://www.flickr.com/photos/35937732@N02/12414398535/" title="Jade Conglomerate by bfesser, on Flickr" target="_blank"><img src="http://farm8.staticflickr.com/7444/12414398535_0f09c2c1b2_m.jpg" width="240" height="180" alt="Jade Conglomerate"></a></td><td><a href="http://www.flickr.com/photos/35937732@N02/12414896554/" title="Jade Clasts by bfesser, on Flickr" target="_blanK"><img src="http://farm8.staticflickr.com/7376/12414896554_8890f0a841_m.jpg" width="240" height="180" alt="Jade Clasts"></a></td><td><a href="http://www.flickr.com/photos/35937732@N02/12414429515/" title="Jade Clasts (wet) by bfesser, on Flickr" target="_blank"><img src="http://farm3.staticflickr.com/2829/12414429515_bb3b7b3711_m.jpg" width="240" height="180" alt="Jade Clasts (wet)"></a></td></tr><tr><td align="center">Conglomerate of <a href="https://en.wikipedia.org/wiki/Actinolite" target="_blank">Actinolite</a> <img src="../scipics/_wiki.png" /> (var. Nephrite)</td><td align="center">Actinolite (var. <a href="https://en.wikipedia.org/wiki/Nephrite" target="_blank">Nephrite</a> <img src="../scipics/_wiki.png" /> Clasts</td><td align="center">show their color better when wet</td></tr></table>

[Edited on 9.2.14 by bfesser]

The past Canadian Thanksgiving Monday I made my mom drive me for 2 hrs up to the Warsaw Caves , an area near Peterborough with really cool limestone Karst formations (Ordovician period). I didn't take many photos because I only had my phone with me, but here are a few:

Here, the jointing in the limestone pavement is very noticeable


The smooth holes in the limestone here are some small kettles. The kettles are not inherent to the Karst landscape; their creation is due to the fact that the whole area was a major glacial spillway during the last ice age. There are a few giant kettles in the area (I did not take photos of them), some of which are large enough for you to climb down into


These next two photos are from within the caves themselves, they aren't very big, and show the limestone bedding.


Please excuse the blurry images!

There is a noticeable absence of fossils in the limestone formations (only rarely you see traces of snails/shellfish in the caves) for reasons which I do not know. Black chert is common in the limestone and you will often see large bands of it cutting through. Also, numerous erratic boulders are strewn throughout the area due to it being a major glacial spillway. It really is an awesome place!


Bfesser, those dendritic samples you have look sweet!

[Edited on 10-2-2014 by blargish]

Quote: Originally posted by Morgan

Some curvy things. They're quite heavy. You can see a porousness to them.

I'm not a big rock collector, but I thought I'd post a picture of a cool (in my opinion) rock.
Here is a rock that I found in my creek.
From what I can tell, it's some calcite grown on an unknown rock, with some mica and iron pyrite (iron II sulfide.)



[Edited on 24-2-2014 by Zyklonb]

I found this curious rock out in the garage among some old sea shells and shark's teeth and wondered what it might be. One "top" face that I didn't photograph just looks glazed like a meteorite but the sides look like bent lines vaguely like petrified wood, or maybe volcanic goings-on. A strong neodymium magnet will not lift it but it's magnetic and heavy.