Florida Agatized Gastropod Seashell Enhydro?

[Bronzviking]

Hello, I found this very unusual seashell on a Tampa Bay beach, Florida. It measures 1 3/4" long by about an 1 inch wide with distinct whorls. It appears to be agatized like the coral I find and is translucent when held up to the light. I than noticed bubbles inside of it which must be water? I spoke to a mineral and fossil vendor and he said it was a enhydro and very rare. What do you think? How was this created and what kind of seashell do you think it is? Thanks! Lynn

[Tidgy's Dad]

Beautiful specimen, that's gorgeous.

I used to have a few quartz enhydros, they were magnificent. One or two had air and water in the bubble so you could watch the water move when you tilted the specimen. 

[MikeR]

Pyrazisiums campanulatus Heilprin, 1887 from the Upper Oligocene Tampa Member of the Arcadia Formation.  Before development around Tampa Bay there were a lot of exposures which yielded beautiful silica pseudomorphs.  I hear that dredging sometimes brings up material.  Great find!  Tampa Bay coral is from the same formation.

 

Mike

[Bronzviking]

3 hours ago, Tidgy's Dad said:

Beautiful specimen, that's gorgeous.

I used to have a few quartz enhydros, they were magnificent. One or two had air and water in the bubble so you could watch the water move when you tilted the specimen. 

Thanks! I thought it was awesome and when you tilt it you can see the bubbles move.

[Bronzviking]

1 hour ago, MikeR said:

Pyrazisiums campanulatus Heilprin, 1887 from the Upper Oligocene Tampa Member of the Arcadia Formation.  Before development around Tampa Bay there were a lot of exposures which yielded beautiful silica pseudomorphs.  I hear that dredging sometimes brings up material.  Great find!  Tampa Bay coral is from the same formation.

 

Mike

Thanks for the info Mike! I find a lot cool stuff after a cold front pushes through.

[FossilNerd]

I didn’t know you could find fossils enhydro like this. Wonderful! 
 

Thanks for sharing! I learned something new and got to see a beautiful fossil! 

[Bronzviking]

17 hours ago, FossilNerd said:

I didn’t know you could find fossils enhydro like this. Wonderful! 
 

Thanks for sharing! I learned something new and got to see a beautiful fossil! 

Thanks! I wasn't aware of this fossil either until I found it and researched it.

[Gregcohen]

You can still find many shells, corals, and vug/geodes with water trapped inside in the Tampa Bay area.  There has and from time to time still is dredging and storms that uncover a large number of agatized specimens that are whole and have a decent chance of being water filled, and will have a bubble inside that you can hear and sometimes see if the agate is clear enough.  Also limestone chunks with them inside buried years ago, and the limestone slowly eroding.

 

I've found some you can see a bubble when back lit, and others that when broken water pours out of.

 

I'm not sure if it's true, but I was told air filled cavities make botryoidal cavities, and water filled make druzy filled.  But it could be mineral concentrations instead.

 

I'm sure the same applies to river ones, but many of those you can not see through.  They have a tendancy of having an outer chert layer.  

 

I try to remember to hold up my coral sticks if whole to check for bubbles since many times they are pseudomorphs with hollow centers.  Always the vug/geodes I prefer are solid agate (sometimes mixed with a little common opal).  Many I find are broken from tumbling on the beach in rocky areas, but I also find complete ones, sometimes still holding water.

 

Shell ones seem a little rarer, but since most have a whole that makes sense.  Maybe if the animal was still in it holding the end closed when buried they would be sealed.