Fossils affected by moistness?

[Psittacosaur9]

I live in a reasonably moist air. It's definitely not tropical levels of humidity, but while I can keep my fossils in mostly airtight areas, I am still worried about them being affected by moistness, especially after reading this thread: https://www.thefossilforum.com/topic/136882-a-sad-day/

 

So, are there any fossils or replicas I should avoid which get destroyed by humid conditions? And, what would be the best way to preserve the fossils I do have or end up getting? I store most of the 'show-stopping' pieces in a display cabinet, and have a couple in storage.

[FranzBernhard]

As said, beware of pyrite / marcasite.

 

Otherwise, most fossils are stable in humid air. I can imagine some problems with montmorilonitic matrix and severe huminity cycling. I don´t know of any problems in that way, though, but I don´t know much.

 

Getting specimens wet (again) is a complete different thing and may lead to destruction.

 

Franz Bernhard

[Ludwigia]

That thread refers to pyritized fossils, which are the ones most prone to disintegrating over time. If you give the appropriate expressions into the search function you will find recipes to slow down the process, but even the scientific researchers haven't been able to find THE final solution. I agree with Franz' statements above, although delicate fossils in soft shale might also be endangered.

[erose]

Although I have mostly had issues with too dry I still save every little pack of desicant and put them with my fossils. The ones in pill bottles are great since they are small.

[hadrosauridae]

Unstable pyratized fossils can never be saved, the process can only be slowed.  Once the fossil is exposed, the self destruction has begun and cant be stopped.

 

Pretty much all other fossils are safe from normal levels of humidity, but trying to control swings by protective housing and humidity controllers never hurt, and may help.

[Psittacosaur9]

Thanks for all the advice!

 

On 10/25/2023 at 6:51 PM, FranzBernhard said:

As said, beware of pyrite / marcasite.

 

Otherwise, most fossils are stable in humid air. I can imagine some problems with montmorilonitic matrix and severe huminity cycling. I don´t know of any problems in that way, though, but I don´t know much.

 

Getting specimens wet (again) is a complete different thing and may lead to destruction.

 

Franz Bernhard

Are there any fossil sites with montmorilonitic matrix which contain fossils commonly able to be purchases? I'd like to know in case I already have any in my collection.

 

On 10/25/2023 at 6:56 PM, Ludwigia said:

That thread refers to pyritized fossils, which are the ones most prone to disintegrating over time. If you give the appropriate expressions into the search function you will find recipes to slow down the process, but even the scientific researchers haven't been able to find THE final solution. I agree with Franz' statements above, although delicate fossils in soft shale might also be endangered.

Yeah, I'll avoid pyritised fossils then. Honestly, the only way I can think of to prevent oxidisation of pyrite would be to keep them in a vacum, although that would be very expensive and would result in the specimens being difficult to research.

 

14 hours ago, erose said:

Although I have mostly had issues with too dry I still save every little pack of desicant and put them with my fossils. The ones in pill bottles are great since they are small.

Ok, thanks for the tip. Next time I get some desiccant, I'll use it to prevent humidity.

 

11 hours ago, hadrosauridae said:

Unstable pyratized fossils can never be saved, the process can only be slowed.  Once the fossil is exposed, the self destruction has begun and cant be stopped.

 

Pretty much all other fossils are safe from normal levels of humidity, but trying to control swings by protective housing and humidity controllers never hurt, and may help.

I already use a de-humidifier in the room containing my fossils, but still thanks for the advice.

[Coco]

My own opinion on pyritized and degrading fossils is the level of sulfur in pyrite. On some sites there is no smell, especially in wet weather, and some pyritized fossils can be stored for decades without problems.

 

However, on other sites, if you smell rotten eggs or sulfur on your hands, fossils will not keep. At a more or less long time, and regardless of what you put in place, they will eventually fall into dust by releasing an acid that will attack what will be around.

 

The chemical formula of pyrite is FeS₂. If the percentage of S₂ is too high, pyrite is not stable.

 

Coco

[Ludwigia]

2 hours ago, Psittacosaur9 said:

Yeah, I'll avoid pyritised fossils then.

I wouldn't necessarily avoid them. They are usually quite pretty and I have many in my collection which are still just fine after more than 30 years of storage. In their cases, a fine coating with a mixture of zaponlack and acetone protects them. You just need to check on them regularly. Just follow Coco's advice.

[FranzBernhard]

6 hours ago, Psittacosaur9 said:

Are there any fossil sites with montmorilonitic matrix which contain fossils commonly able to be purchases?

Sorry, I don´t know.

 

An alternative to vacuum is storing pyrite fossils in thin mineral oil. You may also follow the advice of @Coco and @Ludwigia .

 

Franz Bernhard

[Randyw]

Just as a quick question on pyrite fossils. Has anyone tried using paraloid to protect them?

[hadrosauridae]

9 minutes ago, Randyw said:

Just as a quick question on pyrite fossils. Has anyone tried using paraloid to protect them?

 

yes, its been tried.  I think everything has been tried.  One researcher said that its a self sustaining process.  One the fossil is exposed to air, the process begins and can't be stopped, even if you put it in a vacuum, encase it lucite, coat it, etc.  There are some chemical treatments that will "reset" the clock, but they have to be repeated to continually remove the new contamination. 

[SPrice]

My Yorkshire ammos smell like sulfur when prepping as do the Horn Coral in limestone matrix have strong rotten eggs smell...and so do the Ammonite concretions I recently collected. I'm doomed!  Guess I'll start collecting cereal box tops...I like cereal. 

 

What about storing them in ocean water? lol...jk...

[Ludwigia]

@SPrice Not to worry about your Yorkshire ammos. Mine are still surviving just fine even after 20 years and I've seen some in museums which are much much older.

[Psittacosaur9]

Thanks for the input!

[FranzBernhard]

On 10/27/2023 at 9:08 PM, SPrice said:

Horn Coral in limestone matrix have strong rotten eggs smell

This has possibly nothing to do with pyrite / marcasite but comes from tiny fluid inclusions in the carbonate grains.

Limestone matrix is always good in that way of pyrite/marcasite, it puffers acidity.

 

If a specimen contains only a few isolated specs of pyrite/marcasite, they will possibly disintegrate, creating local damage, but not necessarily complete destruction of the specimen.

 

However, finely divided marcasite/pyrite can be a nightmare like in this (former) polished slab of coal... Width of specimen ca. 13 cm.

Franz Bernhard