Are there any rules to follow when cutting a fossil matrix ?

[Denis Arcand]

I'm trying to reduce my fossil storage space (I have a lot of matrix taking up space in many boxes). The only option I have found is to cut the matrix using a portable water saw with a diamond blade.

 

As I'm new in this field, I'm afraid of doing something wrong.

 

1. What are the rules when cutting a matrix?
2. How near to the fossil can I cut without damaging the fossil?
3. How much of the matrix should I keep for presentation purposes?
4. Rectangular shape matrix are good for storage, but that doesn't feel natural to me, any suggestions ?

 

Here's an example of what I'm talking about

 

Before 

 

 

 

After

 

Edited September 9, 2022 by Denis Arcand

[hadrosauridae]

Its really going to depend on the type of matrix.  Some cut great, some would likely fall apart if you tried.  From the picture posted, it looks like youre good to cut as much as you want.  As far as how much matrix to leave around the fossil, that depends entirely on your needs or your artistic inclinations.  This would fall into the fossil prep world, and if you arent taking 100% of the matrix off, then it become a matter of personal taste in how you want it look.

[FranzBernhard]

We had a discussion about trimming Precambrian fossils (not) too much. A big slab with a small fossil in one corner may not look very aesthetic. But the matrix may contain hidden information not yet retrieved or not yet retrievable. These fossils are quite rare, so there could be a significant loss of information when trimmed.

Franz Bernhard

[Wrangellian]

I agree with the above two... There are no agreed-upon rules that I know of for this procedure, but it is a good idea to balance consideration for the aesthetics and the possibility of removing something that you hadn't noticed, as well as the durability of the fossil/matrix, against your need to make space. At some point in the future, presumably someone else will end up with your fossils, who may not have your particular taste in how to trim them. A person can always cut away more material later, but you can't add it back on.

Even if the surrounding matrix is barren, that still gives you some sense of the taphonomy/depositional environment and relative abundance of fossils in it.

One rule of thumb that I would propose: try to leave somewhat more matrix area than fossil, rather than cutting too tightly (as I've seen enough times), otherwise you may as well prep away all of the matrix (unless it's a 2D compression fossil). But that still leaves a lot of interpretation.

[Ludwigia]

As the others are already suggesting, it's completely up to you how you make your cuts. As to the 4th question, you could trim with hammer and chisel which would look more natural, but you have to be sure that the matrix will split where you want it to rather than through the middle of the plate.

[FranzBernhard]

2 hours ago, Wrangellian said:

try to leave somewhat more matrix area than fossil,

Would you like to elaborate a little bit? I have a picture in my mind: If the fossil is, lets say, 5x10 cm large, leave at least 5 cm of matrix all around it (if possible!), resulting in a specimen of about 15x20 cm large.

 

1 hour ago, Ludwigia said:

rather than through the middle of the plate...

...which is usual case .

 

Seriously, you can cut about half down the slab from the back side and pry the pieces off with a chisel etc. But even with this procedure, well, well....

 

Franz Bernhard

[Wrangellian]

17 hours ago, FranzBernhard said:

Would you like to elaborate a little bit? I have a picture in my mind: If the fossil is, lets say, 5x10 cm large, leave at least 5 cm of matrix all around it (if possible!), resulting in a specimen of about 15x20 cm large.

I don't want to be too particular about it but I was thinking only of the total surface area, though I suppose that could result in less than 5cm around your 5x10cm fossil, which seems a little tight to me...  I like your plan - 5cm of matrix on either side of a 5cm fossil, but, as said, it really depends on the fossil, the matrix, etc. To me, it's more of a concern where you're looking at a natural surface such as a sea-bottom/hash plate as opposed to massive rock with only the one fossil in it. Also I might leave more matrix around a rare/important fossil than around a common one, and I might cut more away from a larger fossil just because larger fossils do take up more space. Really small fossils. why bother cutting away any matrix at all? The rule would tend to break down at the low and higher ends of the size scale.

Edited September 11, 2022 by Wrangellian

[Wrangellian]

I dug out this Utah trilobite to illustrate my way of thinking... I did cut a piece off as indicated. I could cut more off, but this is as far as I could bring myself to trim it so far. There wasn't much to see on the piece I cut off, but on the remainder there are various bits of trilobites and what not, and textures that I am unsure of the nature of, which to me make this an interesting seafloor snapshot.

I'm not wild about the wire brush preparation on the trilobite, but that's another matter. The extra matrix kind of compensates for that, though if I could find one that was prepped better (or left unprepared) I would trade this one for it, even if it was on a smaller piece of matrix, but I do like extra matrix if available.

Lying flat, it would take up a fair amount of drawer space at a little more than 21x12cm, but if I could find another one of those plastic plate stands, I could prop it up on that to save a little space, but the ones I have are spoken for.

 

Edited September 12, 2022 by Wrangellian

[FranzBernhard]

1 hour ago, Wrangellian said:

I dug out this Utah trilobite to illustrate my way of thinking...

This is a very good illustration, thanks so much!
Franz Bernhard

[Wrangellian]

On 9/11/2022 at 10:49 PM, FranzBernhard said:

This is a very good illustration, thanks so much!
Franz Bernhard

Thanks Franz, I appreciate hearing that. (or reading it!)