How Many Different Ways Can A Fossil Become Mineralized?

[Mediospirifer]

Most people don't read much when there's the real thing to look at, but there are some who do. Just because I didn't notice anyone reading the board display doesn't mean that nobody did!

I did see one pair, possibly mother & daughter, reading their way through my microfossils display while I was talking to someone else at the other table. When I finished answering his questions, I saw the daughter sitting at the microscope, totally focused on looking at all of the micros I brought! She didn't even look up when I came over to say hello, and her mother just gave me an uncertain smile--I think she was concerned that I might not want kids playing with the scope. I gave her a grin and told her to let me know if she had any questions. I was more concerned about the little kids that wanted to look, like one toddler who climbed up on the chair, then grabbed the microscope eyepieces to pull himself up! Fortunately his mother was within arm's reach and caught him before he knocked anything over.

There was also one man who had some questions for me. I hadn't seen him looking at things, but he was asking for more details about specific things I had written, so he must have read some of it while I wasn't watching.

There was one kid I found a bit amusing. He might have been around 6, and he lit right up when I told him how I planned to break up my limestone chunks: wrap it in canvas and whack it with a sledgehammer. He broke into a wide grin, took a fast look around, then looked at me and asked, excitedly, "Where are the hammers?" I had to explain to him that I hadn't brought hammers with me, just a chunk of matrix to show what to look for in the field. He was disappointed with that, but he did like my micro shark teeth.

One visitor who arrived while I was still setting things up asked what I had, and responded to the mention of microfossils with "Oh! I love microfossils!" And there was a man who came by while I had my scolecodont case under the scope, who was surprised and pleased when I told him (before he looked into the scope) that the pieces in the case were 350 million year old polychaete worm jaws. "Hey! I've looked at polychaetes!"

And we had one TFF member come by for a visit, who came up to me and asked if I was from the Forum. It was fun to meet another Forum member and show her my macrofossils.

Other club members had brought their own setups for various minerals. Two people had boxes of mineral specimens for sale, one man had a display of different granites (it's impressive how much variety there is in granites!), another man had a lapidary setup with his gem-faceting machine, inviting people to try it, there was a club membership table with a few things for sale, and there was a kids' table with crystal shape paper models that the kids could color and fold.

Overall, a lot of fun was had by everyone.

I'll post more pictures after I've unpacked things. I think I'll set my main display case back up for photographing before I put things away. I'll also post a few pictures of my microfossiling tools.

[ckmerlin]

Lots of good suggestions here! Thanks, everyone!

Amber, coal and stromatolites I had thought of, oil not so much. Peat I hadn't really thought of as fossil material, but yes, I can see that it could be.

Mikeymig, I would love to see a photo of that horse jaw!!! I'd never heard of turquoise as a replaement mineral before--agate, jasper, chert, flint, chalcedony, opal, and pyrite, yes, but not turquoise. Is that in the jasper family of minerals? I may have to do some more research!

I have some fluorescent fossils, including an oreodont jaw, unfortunately, the room where we're doing the open house event is too brightly-lit to show them effectively. Maybe by next year I'll have a dark-box for fluorescent displays.

I do have some Peace River Pleistocene fossils (deer bones, horse teeth, a partial mammoth tooth, plus others presently unidentified), does anyone know offhand what the minerology is there? Obviously, they're not completely mineralized, but some of the bones feel heavier in my hand than I'd expect for unaltered bone.

Something else I'll include (if I can locate it!) is a piece of tiger iron (made into a pendant, so not in with the rest of the rock collection). I've had it for years because it's a cool-looking rock. A month ago I found it mentioned in a book about jaspers, as an example of the Banded Iron Formations (also known as Red Beds), laid down during the original atmosperic oxygenation event! I've wanted a piece of Red Bed since I first heard about them, and it turns out I've had a piece all along! The original trace fossil?

Thanks for the help, folks!

Hi I think turquoise is a phosphate mineral looks like you had a great day too excellent job

[Mediospirifer]

Hi I think turquoise is a phosphate mineral looks like you had a great day too excellent job

Thanks! It was a great day.

I looked up fossil turquoise after seeing mikeymig's mention above, and found an article on Mindat about it. According to the author, "bone turquoise" or odontolite isn't the same mineral as the true turquoise. Chemically, it's a fluorapatite with impurities. The element that gives it the blue color is manganese. Fluorapatite is the usual mineral in badlands vertebrate teeth.

I leaned a lot in the course of putting this show together!

[Auspex]

...I leaned a lot in the course of putting this show together!

As did we all

[Mediospirifer]

Here are a couple more pictures.

This is the third board from the meteorite display:

And these are two views of my fossil case:

If anyone wants more detailed photos of the rocks (either fossils or meteorites), I'll be happy to take a bunch and post them. I plan to take a few photos of my homemade microscopy tools, too.

[Wrangellian]

Nice displays!

I think your 'opalized ammonite' is a Cleoniceras besairei from Lower-Mid Albian of Ambarimaninga(?), Mahajunga, Madagascar.

[Mediospirifer]

Nice displays!

I think your 'opalized ammonite' is a Cleoniceras besairei from Lower-Mid Albian of Ambarimaninga(?), Mahajunga, Madagascar.

Thanks!

That one didn't have a label when I bought it. It was one of several in a dish for $3 each at a local gem & mineral show! I'm happy to have it identified.

Do you think it is opalized, or is that the original shell material recrystallized? I thought it was opal when I bought it, but comparing to my Australian opalized clams, I'm not so sure.

[Mediospirifer]

Nice displays!

I think your 'opalized ammonite' is a Cleoniceras besairei from Lower-Mid Albian of Ambarimaninga(?), Mahajunga, Madagascar.

Here's a closer picture of the ammonite, showing the other side. I also have another one tucked away in my fossil drawers.

[Wrangellian]

Yes I'm pretty sure that's a C. besairei, from the info I can glean. Lots of them available at rock shows but many fossils available at such shows don't have enough info for my liking (esp. the more important bit: location, eg. something more specific than 'Madagascar'!). It's bad enough I have fossils acquired in my youth that I have lost the info that did come with them... The other problem these often have is the aperture has been unnaturally squared off, like yours. Yecch! I was lucky enough to find one that is natural (if incomplete) but the prep job was a little crude. No win.

As I understand it, the pearly ammonites retain their aragonite shell (nacre) more or less unaltered. I don't think it's the same thing as opal but it's the same sort of effect.

Edited February 7, 2014 by Wrangellian

[Mediospirifer]

Yes I'm pretty sure that's a C. besairei, from the info I can glean. Lots of them available at rock shows but many fossils available at such shows don't have enough info for my liking (esp. the more important bit: location, eg. something more specific than 'Madagascar'!). It's bad enough I have fossils acquired in my youth that I have lost the info that did come with them... The other problem these often have is the aperture has been unnaturally squared off, like yours. Yecch! I was lucky enough to find one that is natural (if incomplete) but the prep job was a little crude. No win.

As I understand it, the pearly ammonites retain their aragonite shell (nacre) more or less unaltered. I don't think it's the same thing as opal but it's the same sort of effect.

Interesting!

I honestly didn't notice the sawed-off aperture when I bought it. I just saw that opalescence (and the price) and decided that one of them had to come home with me. Looking at the squaring off, I may turn it into a jewelry piece. I could hide that cut-mark with some wire wrap while showcasing the color of the shell... I'll have to keep my eyes open for an intact one when I go back to the shows.

[collector]

We had a good time at the museum last week. Your display was great. I enjoyed seeing your microfossil setup. It seems like you are having a good time with them. Thanks for showing us.

Patti

[Mediospirifer]

We had a good time at the museum last week. Your display was great. I enjoyed seeing your microfossil setup. It seems like you are having a good time with them. Thanks for showing us.

Patti

We had fun with it! I enjoyed showing them to you. Thanks for coming!

[Mediospirifer]

Now that I've had a day when I've 1: been at home during daylight, 2: had fresh batteries for my camera, and 3: had a few hours free, I've taken pictures of all of the rocks from my display case, with the labels. Time for a major posting run! (I do mean major, there are almost 80 photos! This will take several comments. )

I'll start with an example of shale preservation:

Trilobite

Elrathia kingii

Cambrian

Millard Co., UT

Next, my best siderite nodule:

My Green River Knightia as a beauty piece:

Daylight pictures of my Cleoniceras besairei ammonite, misidentified as opalized:

A tar bug from La Brea:

And a pair of deer calcanea from the Peace River:

More in the next post!

[Mediospirifer]

Here's a horse tooth from the Peace River:

And some Florida shells that still have color. The two unlabeled shells are Olive shells (Oliva sp.):

More to come next post!

[Mediospirifer]

Here's a scallop that still has original material:

Here's a rock with a few brachiopod casts. This is one of two rocks in my display that I found rather than bought or traded with friends:

And some gastropod endocasts. This one is from Australia. If anyone can identify it, I'd be pleased to hear! :

This is a Hormatomas sp. endocast:

More endocasts to come!

[Mediospirifer]

Here's a Holopea pyrene endocast:

And a Turritella sp.:

Next are some compression fossils. Here's a piece of tree fern bark from a coal bed:

And here's the other fossil in the display that I found. Yes, there's an Eldredgeops rana cephalon in the piece, but it's the amorphous black-and-rusty streak that I intended to have here. I didn't know what it was when I found it, but I've since learned that it's a piece of carbonized wood (Middle Devonian, Moscow Fm.):

Next up: Leaves!

[Mediospirifer]

Here are some leaf impressions from an unknown source. I bought them because they were nice-looking, and I didn't have many leaf fossils. I wasn't originally planning to include these in my display, but changed my mind after doing my background research. I looked at a lot of different fossil pictures online, then went back to look through my cabinet to see if I had missed anything--and when I looked at this piece, I realized that it looks like a piece of the John Day fossil beds in volcanic ash:

I also have a few Australian Glossopteris leaves:

Here's the start of my trace fossils display. Bird tracks from Utah:

More trace fossils next.

[Mediospirifer]

Coprolites!

And a couple of gastroliths:

Here's a couple pieces of Banded Iron Formation. Yes, the small one is a piece of tigereye. At the show, I also had a large chunk of tiger iron in the case, borrowed from another mineral club member.

Last for this comment, I have some double fossils: shells with predation marks. Trace fossils preserved in fossils!

More shells with traces next.

[Mediospirifer]

Here's a bivalve shell that something burrowed into:

And here's a gastropod with different burrowing marks:

My last trace fossil at the show was this insect cocoon. I think the hole is from predation rather than hatching, since modern cocoon-spinning insects tend to emerge from one end, not the side. This would then be a double trace fossil!

I could be wrong about this.

Here are my amber pieces. First, the bugs!

This one's Polish:

Dominican:

And some pieces with interesting color of unknown origin:

More amber next.

[Mediospirifer]

Here's some yellow amber of unknown origin:

And a few pieces of copal (with bugs) from Madagascar:

Now to get into the replacement fossils. Here's a nice chunk of Favosites replaced by calcite:

And a Silex sp. clam in silica:

More to come!

[Mediospirifer]

Another silicified fossil:

Here's one of my vertebrate fossils. The teeth have been replaced by fluorapatite. This one is fluorescent!

I have several fossils replaced with jasper. Here's a colorful piece of polished dinosaur bone:

A nice polished slice of "Turritella Agate", with fossil gastropods that aren't Turritella, in a matrix of jasper, not agate!

And some polished pieces of stromatolite in jasper:

Next up: Petrifield wood!

[Mediospirifer]

Here's a piece of petrified wood replaced with jasper:

And another one:

A very pretty pyritized ammonite:

Next, agates, opals, and hematite!

[Mediospirifer]

Here are some agatized gastropods, of unknown origin:

Here's a nice piece of agatized coral from Florida:

And some more colorful agatized coral, also from Florida:

Three broken clam fossils with nice opal fire from Australia:

And a small ammonite replaced with hematite:

That's the full set. I'll photograph and post my homemade microfossiling tools sometime soon.

[Ludwigia]

I'm arriving a little late here, but better than never . That's really a great collection of samples you've got there and also very well organized! Thanks for sharing!

[Mediospirifer]

I'm arriving a little late here, but better than never . That's really a great collection of samples you've got there and also very well organized! Thanks for sharing!

Thank you!

I'm afraid that my long-term storage drawers aren't that well organized. It made sense to group them by type here, but when I put them away the question is really "Where can I fit this in?" On the plus side, looking for a particular rock frequently leads to revisiting cool things that I didn't remember buying! Especially if my husband has rearranged things "sensibly" since I last looked....