Please help to identify these fossil balls

[Chunkette]

I collected these beautiful ball-style fossils a few years ago from around the Hajar mountain area in Oman. I still don’t know what exactly they are. They were just lying in amongst the desert sand within the mountain (known for marine fossils from the Eocene to Miocene age) I’m guessing maybe they’re a type of solitary sponge or coral? I would be so grateful if someone could please help with the identification. I’ve taken as many photographs as possible, including some cross sections from broken fossils. The last 2 photographs show an additional species of fossil ball which I cannot identify either. The 2 new mystery ball fossils appear to have trapped other small marine fossils (nummulites) inside their fossilised bodies. Thank you so much for any information you can offer. 

Edited May 8, 2020 by Chunkette

[GeschWhat]

Those are very interesting. I can't wait to see what the experts say! 

[sharkdoctor]

15 minutes ago, GeschWhat said:

Those are very interesting. I can't wait to see what the experts say! 

Same here!

[hadrosauridae]

Looks like coral.

[Sacha]

I think they look crystalline, and suspect they are a form of evaporative mineral like gypsum.

[oyo]

If Eocene perhaps this:

 

[marguy]

2 hours ago, Sacha said:

I think they look crystalline

I agree, maybe calcit/ aragonit  (have a test with acid or vinegar ) or gypsum

 

[Planko]

That is a very long mountain range. Can you narrow it down? When you say "amongst the sand," do you mean covered or laying on top? Mixed end like you see part but not any of it? 

 

 

[Chunkette]

4 hours ago, Planko said:

That is a very long mountain range. Can you narrow it down? When you say "amongst the sand," do you mean covered or laying on top? Mixed end like you see part but not any of it? 

 

 

Yes, Jebel hafeet. They were laying on the top of the sand/gravel in between fallen rocks from the mountain (I’ll attach photo of sand/gravel area)  spread over roughly a 30 metre area. A lot of them were in small groups and looked as though they’d rolled down the mountain from when rocks had fallen from above (Recent partial rock fall in the last 5 years). The majority of the fossils appear to be made of dark grey/black crystal (dogs-tooth type) structures radiating from several central points.  I have seen around 300 ball fossils in the sand/gravel. I have not seen similar fossils in any other parts of the mountain; They seem to only come from this one small area. From the exact same site as I found an Eocene tiger shark tooth. (I’ll attach a photograph)  I think I have a photograph of one of the crystal ball fossils in situ -  It was an unusual ball fossil, as it looked as though it was joined with another ball fossil stuck on top of it. All the others are solitary. 

[Pemphix]

Some kind of a "desert-rose" i think.

I don't think that it is a fossil..

 

[Ludwigia]

Fascinating. I agree that these balls are composed of either gypsum(does it feel soapy at the touch?) or calcite(does it fizz in vinegar?). A simple test will tell.

[westcoast]

Search images for desert rose selenite

[Chunkette]

3 hours ago, Pemphix said:

Some kind of a "desert-rose" i think.

I don't think that it is a fossil..

[Chunkette]

Thank you for the replies. I have carried out the vinegar test on a broken piece of crystal and it did fizz in the vinegar. 
 

 

[Planko]

Thank for answering my questions. I was thinking something similar to the Desert Rose referred above but I am not familiar with Gypsum forming crystals like that. 

 

Those are really neat specimens. Nice finds. 

[Ludwigia]

9 hours ago, Chunkette said:

Thank you for the replies. I have carried out the vinegar test on a broken piece of crystal and it did fizz in the vinegar.

So it must be calcite, since gypsum doesn't react with vinegar.

[Chunkette]

3 hours ago, Planko said:

Thank for answering my questions. I was thinking something similar to the Desert Rose referred above but I am not familiar with Gypsum forming crystals like that. 

 

Those are really neat specimens. Nice finds. 

Thank you. May I ask your thoughts on what you think they may be in that case? As ‘Ludwigia’ pointed out: the crystals must be calcite, since gypsum doesn’t react with vinegar. (I carried out the vinegar test and the crystals did fizz in the vinegar).

Thank you for taking the time to read and answer my questions! 

[Chunkette]

2 hours ago, Ludwigia said:

So it must be calcite, since gypsum doesn't react with vinegar.

Thank you. Please can you tell me why the calcite might have formed in the first place? I had thought that calcite formed in fossils in place of soft tissue during the fossilisation process, but I now think that is incorrect? I wonder why the calcite crystals are a smokey grey colour? Sorry for asking so many questions and thank you for taking the time to read this. I wonder what the mystery balls are! 

[Ludwigia]

6 hours ago, Chunkette said:

Thank you. Please can you tell me why the calcite might have formed in the first place? I had thought that calcite formed in fossils in place of soft tissue during the fossilisation process, but I now think that is incorrect? I wonder why the calcite crystals are a smokey grey colour? Sorry for asking so many questions and thank you for taking the time to read this. I wonder what the mystery balls are! 

I'm afraid that I'm not well enough versed in minerology to be able to explain to you exactly why the calcite appeared in this form, but basically it depended on the particular circumstances in the surrounding sediment at the time of conception. The main thing in this case is that the balls built up layers of single crystals radially around a core (see the split one) to create a so-called crystal aggregate. They are calcite simply because the ingredients were available from the surroundings. Mineral solutions also often include impurities which they picked up on the way, which explains the color.

[oyo]

This is Stylocoenia "ball" coral from Spain´s Eocene (Bartonian).

As you will see, it are very similar to your specimens. You should consider this possibility for your material. Try to find the columns of the intersections of the chalices or, at least, the bases of them. 

Edited May 10, 2020 by oyo

[Planko]

While drinking coffee and scrolling through the web I found two interesting things to look at. I could be off here. 

 

Calcite Echinosphaerites

Echinosphaerites aurantium

 

There are a few pictures that show the same crystal formation in balls. Most of the picture show perfectly round balls probably due to being in the element more than your finds. I think one person referred to them as sea balloons during his research. 

[Chunkette]

On 10/05/2020 at 11:39 AM, Ludwigia said:

I'm afraid that I'm not well enough versed in minerology to be able to explain to you exactly why the calcite appeared in this form, but basically it depended on the particular circumstances in the surrounding sediment at the time of conception. The main thing in this case is that the balls built up layers of single crystals radially around a core (see the split one) to create a so-called crystal aggregate. They are calcite simply because the ingredients were available from the surroundings. Mineral solutions also often include impurities which they picked up on the way, which explains the color.

Fascinating! Thank you for the information. 

[Chunkette]

On 10/05/2020 at 1:27 PM, oyo said:

This is Stylocoenia "ball" coral from Spain´s Eocene (Bartonian).

As you will see, it are very similar to your specimens. You should consider this possibility for your material. Try to find the columns of the intersections of the chalices or, at least, the bases of them. 

Excellent, thank you. Yes, there are similarities. I will do some research on Stylocoenia and try to compare it to the balls I have. Thank you once again. 

[Chunkette]

On 5/10/2020 at 7:53 AM, Planko said:

While drinking coffee and scrolling through the web I found two interesting things to look at. I could be off here. 

 

Calcite Echinosphaerites

Echinosphaerites aurantium

 

There are a few pictures that show the same crystal formation in balls. Most of the picture show perfectly round balls probably due to being in the element more than your finds. I think one person referred to them as sea balloons during his research. 

Very exciting! I wasn’t even aware that those types of fossils even existed. There are similarities, especially in the crystal formations of the cross section photographs of Echinosphaerites aurantium. 
 

The plot thickens as to what the mystery balls are!

 

Thank you for taking the time to do some research. Much appreciated.