Spectacular ammonites

**neuropteris** · Feb 24, '07, 1:30pm

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** · Feb 24, '07, 9:57pm

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

**tonmo** · Feb 24, '07, 10:02pm

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** · Feb 24, '07, 10:07pm

Originally Posted by tonmo

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** · Feb 24, '07, 10:14pm

[QUOTE=tonmo;88436]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** · Feb 24, '07, 10:58pm

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

**Phil** · Feb 25, '07, 6:22am

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

**neuropteris** · Feb 25, '07, 12:21pm

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** · Feb 25, '07, 9:32pm

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!