Matrix Identifcation

[Steve D.]

Howdy! I'm having a heck of a time identifying the matrix surrounding the fossils I'm finding in my dig site. I'm using vinegar but it is weak. I'm considering using CLR on some practice stone plates but I could use some guidance. 

[Kane]

There are stronger acids to use, and cleaning vinegar rates at about 10% (or double that of table vinegar). That being said, I would advise caution using acids on limestone if the fossils themselves are also composed of calcium carbonate as it will eat through those as well. Possibly a better option for revealing fossil details in matrix is to use abrasion. I can't really tell clearly by your pictures if you are trying to better demarcate the fossils in a hash plate or attempting to free the fossil from matrix entirely. If the latter, scribes and abrasion are the better route as it offers a bit more control than the use of acids in most cases.

 

If the second picture is what you are trying to work at, these are mostly impressions, so that would rule out trying to free them from matrix entirely. Perhaps show some of the other pieces you are working with and we can recommend the best approach.  

[ynot]

1 hour ago, Steve D. said:

identifying the matrix surrounding the fossils

It looks like limestone, but there are a few other rocks that can look like this.

Does it fizz when You put the vinegar on it? If not then acids may not have any effect on it.

1 hour ago, Steve D. said:

I'm using vinegar but it is weak.

What are You trying to accomplish with this? 

 

1 hour ago, Steve D. said:

I'm considering using CLR on some practice stone plates but I could use some guidance. 

All acid product containers will have a triangle with a number in it on them. Make sure any plastic containers You use have the same markings as the acid container.  

The evaporates will get on any nearby surfaces and can rust any iron or dissolve other materials.

Keep a good supply of baking soda to neutralize any spills or pieces that come out of the acid.