Spectacular ammonites

[neuropteris]

Hello all

As Kevin mentioned in his thread its a bit quiet out there in dead ceph land. I for one haven't been out and about as much as I should have and have found squat diddley for months. Here are 3 of the more spectacular ammos on my shelves. All acquisitions, can't claim to have found any of these but they do look very nice even if I do say so myself.

First a Caloceras sp from the Lias of the south of England. 8cm at its widest point and showing the irridesence that that particular locality is famous for.

Second is a monster Cadoceras sublaeve complete to the mouth border. The coin is 2cm for scale. Comes from the Jurassic Kellaways formation of Wiltshire

Thirdly a spiney Sonninia from the Oolite of Dorset. Preserved in calcite and once again the coin is 2cm

All the best

Andy

 

[Architeuthoceras]

Great ammonites you have there Andy. Always nice to see shells with that irridesence.

 

[tonmo]

Those are beautiful. I need to get myself an ammonite fossil...

Where does that irridesence come from? i.e., is it formed over time, or...? How does that come about?

 

[Architeuthoceras]

Where does that irridesence come from?

Great, great, great, great, great... Grandmother of Pearl.

Although it is probably calcite replacing the original aragonite, but it keeps the same crystal form so the light refracts or reflects the same colors.

 

[sorseress]

Those are beautiful. I need to get myself an ammonite fossil...

How big of an ammonite do you want? I have several and can easily get more. Matter of fact, I was going to bring several small ones to tonmocon to use for doorprizes or whatever....
Ortheceras too.

 

[tonmo]

Any size... I gotta start with something! Let's PM and transact!

 

[Phil]

Wow, stunning Andy! That first ammonite, is it coated with anything to preserve it?

 

[neuropteris]

I don't know for certain but I suspect its had a light coat of varnish. The colours are all natural though. I'd love to know how they got the matrix that smooth.

I knew someone was going to ask how the irridesence occurs so thanks Kevin for saving me the job of looking it up You can occasionally find a mother of pearl effect on Yorkshire coast Dactylioceras though its pretty rare and only affects a small portion of the ammonite.

Andy

 

[fluffysquid]

if you like your ammonites colorful.... I picked up a partial ammonite in Canada last year with a shocking amount of iridescence. A few companies market it as Ammolite in jewelry. nice pictures here: http://en.wikipedia.org/wiki/Ammolite

I also picked up a lesser piece set in a pendant than is pictured there... it only flashes green, blue, and purple!

 

[neuropteris]

Ammolite ammonites are also quite stunning. I've seen a few on the web but they cost a fortune. Maybe when I've won the lottery......