Petrified Wood questions

[Kato]

15 minutes ago, ynot said:

This looks more like a mineral deposit than petrified wood.

Can You post additional pictures?Close ups and the other sides.

I'll need to do these again in natural light and with my macro lens on. For now...

 

Side view

 

Zoom into upper area. 

 

Under magnification it appears that towards the top there are 'slivers' of grained brown material interwoven in parts of this specimen.

 

This is a sedimentary environment with high iron content permineralization. 

 

 

 

[Kato]

23 minutes ago, ynot said:

This looks more like a mineral deposit than petrified wood.

Can You post additional pictures?Close ups and the other sides.

Here is an in situ pic where the material came from

 

[ynot]

OK, please disregard My last post.

[Kato]

Just adding a couple of red permineralized specimens from a new location.

 

 

[Kato]

This one has the appearance of a well marbled steak. About 8" at the widest.

 

 

 

[Kato]

At the boundary between lower and middle Pennsylvanian I have chanced upon a number of what are likely fern. Therefore, temporarily presuming Psaronius

 

This specimen 6" wide 

 

End view of the above

[Kato]

Greenish cast to the druzy coating of a specimen

[Kato]

Possible Stigmariodes specimens encircled potentially indicating Psaronius rootlets

 

End view of one of many exposed specimens in area. Diameter approaching 20".

[Kato]

Specimens also entrapped between overhanging formations and carbonate bedding. This one almost 24" long.

[Kato]

Specimens up to 48" long exposed

[ynot]

Nice pieces of petrified wood You found.

[Coco]

Hi,

 

What are these green brown minerals ? May we have close-up ?

 

Coco

[abyssunder]

7 hours ago, Coco said:

What are these green brown minerals ? May we have close-up ?

Are you thinking of Glauconite?

[Kato]

8 hours ago, Coco said:

Hi,

 

What are these green brown minerals ? May we have close-up ?

 

Coco

Coco, these are from iron deposition during the permineralization of the specimens.

 

Colors associated to various ratios of hydrogen, iron, manganese, oxygen, silicon and sulfur.

 

The green tinted quartz crystallization. Photo taken under sunlight so color skewed more toward yellow spectrum. In real life more of an olive green color.

[Kato]

7 hours ago, Coco said:

Hi,

 

What are these green brown minerals ? May we have close-up ?

 

Coco

Brown tinted quartz crystallization

[Kato]

Macro on green crystallization

 

Macro on brown crystallization

 

 

 

 

 

[Coco]

Hi,

 

Sorry, I can’t see the crystalline shape, so I don’t know what it is.

 

Coco

[Kato]

5 hours ago, Coco said:

Hi,

 

Sorry, I can’t see the crystalline shape, so I don’t know what it is.

 

Coco

Hi, they are quartz crystals.

[Coco]

Ah OK !

 

Coco

[ynot]

On 2/20/2019 at 3:40 PM, Kato said:

The green tinted quartz crystallization.

This looks like the green is an encrusting mineral on the white mineral, possibly glauconite.

I wonder if the white mineral is calcite. Can You do an acid test on it? (Same for the "brown" mineral.)

[Kato]

2 hours ago, ynot said:

This looks like the green is an encrusting mineral on the white mineral, possibly glauconite.

I wonder if the white mineral is calcite. Can You do an acid test on it? (Same for the "brown" mineral.)

Here is a zoom on one of the greenish crystals. This is the best I can do with my equipment and these crystals are very tiny. Note the crystal with the red line above it. 

 

It appears to show the expected trigonal habit of a quartz crystal.

 

For a sanity check I re-ran both brown and green crystals with vinegar and they are both non-reactive.

 

If they had a 100% covering of glauconite I do not know what the reaction to vinegar would be. Any ideas? FYI, I did have some glauconite sandstone on -hand and it appeared to be non-reactive when tested.

 

I then picked an obscure location to attempt a hardness test. My pocket knife did not appear to scratch any of the crystals nor remove any 'coating'. It was also difficult to flake off an individual crystal. That crystal remained intact. 

 

For grins, I turned over the specimen to the least interesting side and found that it has primarily black and red colored crystals (the red appearing almost as if iron oxide). Also, crystals appeared to be trigonal under my most extreme hand magnifier and could not be scratched and non-reactive to vinegar...I have one really clean specimen now. 

 

As a sidebar, I did find interesting clumps of iron material on the back side. I believe they may be forms of botryoidal hematite. These are formed as spheres or mounds of spheres. I'll post a few photos but they won't be very good due to lack of proper lighting.

 

I will need to wait until daylight to take higher quality macro pictures.

 

 

 

 

Further inspection shows much more botryoidal hematite than original look. I also believe I found a small clump of green crystals adjacent to a hematite grouping. Definitely will need natural light for that photo.

 

 

[ynot]

OK, sounds like quartz. Just wanted to be sure.

I agree with iron mineral for the black mineral. Thinking the last picture with green maybe lichin.

[Kato]

On 2/21/2019 at 10:59 PM, ynot said:

OK, sounds like quartz. Just wanted to be sure.

I agree with iron mineral for the black mineral. Thinking the last picture with green maybe lichin.

Well, the vinegar did not kill the potential lichen. It remained green so it is some kind of other crystal. Not important...

 

I do understand more the scenario for the formation of the mineralization. In this photo, you can clearly see a crinoid captured in the quartz sandstone matrix. This seems to indicate, at a minimum, a surge of seawater to rapidly bury the lycopsid in the photo allowing for a nice level of preservation. The crinoid+quartz sandstone formation is about 3 feet thick.

 

The lycopsid is visible in the lower left of this photo. The exposed section is about 14" tall 

 

Above that is a nice clean quartz sandstone formation 2-3 feet thick about with another small bench of permineralized plants.

 

[Kato]

About 100 feet west of the above location I found this crazy intermix of terrestrial and sea life (crinoids, horn corals, small brachiopods).

[ynot]

48 minutes ago, Kato said:

Well, the vinegar did not kill the potential lichen. It remained green

Lichens are a very hard thing to kill. I have seen them survive an acid bathe (muratic).

Get one wet and scrape it with a needle. If it is a mineral it will be hard, lichen will soften when wet.

 

Nice crinoidal sandstone.