Question about horn shape of abalone pearls

[New Zealand Natural Pearl]

Conical Formation

Conical Formation

Hi
Firstly replying to Gem Geek - Yes the abalone has been turned
upside to show you how they lye underneath.
You will note green gonad is female - white is male as in this photos

Steve - Membrane/mantle is the same - not the shell.
The inside of the conical is actually the starting point
of the pearl. If you like we will cut one in half and show
what happens.

Tango - Your photo - What is the size of the shell?
Where was it farmed?
what specimen of abalone and age?

It is possible to culture conical pearls in Farmed Abalone

 

[SteveM]

If you like we will cut one in half and show
what happens.

Tango - Your photo - What is the size of the shell?
Where was it farmed?
what specimen of abalone and age?

It is possible to culture conical pearls in Farmed Abalone

Absolutely, it would be great to see a cross section. If you have a good X-Ray, also! To answer for Tango he is working with H. rufescens, exactly where in Chile I'm not sure. He will need to provide that info along with size.

Cultured conical pearls? What's the precedent?

 

[Tango]

Hi New Zealand,
The shell is about 11 cm and farmed in the VI region of Chile and as Steve says it?s H. rufescens.

 

[New Zealand Natural Pearl]

Conical

Conical

Here 4 images of cross sections of a conical pearl. Onces again we have abserved the small individual pearl structure inside a conical. As in our image from the post "pearl factory" , you can see how the top of the conical splits on both sides. This tells us a lot about its construction. We estimate the pearl to be at least 7 years old and it is about 15 mm in length.
We are looking forward to your comments

 

[SteveM]

Thanks so much for sacrificing that pearl, its two sides hopefully will yet find good use(s).

The images appear compatible with the conjecture earlier in the thread (i.e. nacre formed around a diseased/cystic hepatopancreas?thereafter decayed?by the gonad's interior-wall epithelial cells converted to biomineral functionality).

An alternative explanation for how these pearls take on the shape of the gonad is not clear to me at the moment.

 

[Lagoon Island Pearls]

Thanks guys for posting these excellent photos along with your observations.

 

[GemGeek]

I agree with Dave. Fascinating.

 

[Tango]

Good pictures!,
Thank you for posting them.
For me looks like in a first moment the animal was fighting the disease and after he controled it with the nacar, like a "quiste" (from spanish).

 

[New Zealand Natural Pearl]

Conical - Gonad

Conical - Gonad

Hi There,
Inside of Our Photo is not a disease, simply the small nodules of
calcite. Refer - to Thread Mr Hill - Natural Abalone Pearls. Our
Natural Pearl Factory - 09.07.2009
The Formation of a natural pearl is quite simple -

In Tangos photo the animal is not producing nacre and is about to
die - not from disease but the change to the mantle.
Steve - we will send half of the conical pearl we cut to Ken, at GIA,
Thailand you are most welcome to the other half.
Remember simple language is easier to understand for the majority
of the forum - too technical is confusing.

 

[SteveM]

hi there - re read this - the process of natural pearl is simple

Bringing your new post at Natural Abalone over here via the quote above. Doubts seem to be crossing in the night?the provocation of excess nacre secretion in defense of predators is not at issue, rather its occurrence within the gonad.

Are the theories and photos provided intended to demonstrate that horn pearls do NOT form in the gonad but rather obtain their gonadal shape in another manner?contrary to CIBJO definition and the California diver's observation?

 

[SteveM]

In Tangos photo the animal is not producing nacre and is about to
die - not from disease but the change to the mantle.
Steve - we will send half of the conical pearl we cut to Ken, at GIA,
Thailand you are most welcome to the other half.
Remember simple language is easier to understand for the majority
of the forum - too technical is confusing.

On the other hand, things are not getting much clearer here! Apologies if I'm just being a bit slow.

Of course I would welcome the specimen, if only temporarily, as I would be able to offer it for examination by the nacre scientists at University of Granada during my visit there late next month.

The shape of the pearl that was cut neither appears to be the typical gonad/horn, but rather seems more elongated and rectangular?

 

[Lagoon Island Pearls]

The shape of the pearl that was cut neither appears to be the typical gonad/horn, but rather seems more elongated and rectangular?

Agreed. Those pearls were likely formed as a result of soft tissue strain or perforation, by an environmental stress.

So yes Steve, the question of what causes hepatopancreatitis in abalone is still up in the air.

I'm still leaning towards systemic as opposed to physical, whether parasitical via ingestion or an auto-immune response to blood acid/base balance.

 

[Tango]

Hi Steve,
I?m still waiting for new shells to send you, I haven?t gone to the farm yet but I asked to some workers there to search some for you.

 

[SteveM]

Tango,

Much appreciated! Remember, the objective is to demonstrate the formation of nacre inside of the gonad.

Still wondering about this statement from NZ Natural Pearl:

It is possible to culture conical pearls in Farmed Abalone

 

[New Zealand Natural Pearl]

Thanks so much for sacrificing that pearl, its two sides hopefully will yet find good use(s).

The images appear compatible with the conjecture earlier in the thread (i.e. nacre formed around a diseased/cystic hepatopancreas?thereafter decayed?by the gonad's interior-wall epithelial cells converted to biomineral functionality).

An alternative explanation for how these pearls take on the shape of the gonad is not clear to me at the moment.

We were trying to point out by showing the "pearl factory" that, inside a pearl any
shape or form may look like this in a natural pearl - people mistake 'the look' for
"diseased"

 

[SteveM]

We were trying to point out by showing the "pearl factory" that, inside a pearl any shape or form may look like this in a natural pearl - people mistake 'the look' for "diseased"

Again, further explanations are needed as concepts remain rather unclear. I do admire the seemingly unique ability of Haliotis to utilize calcitic spherules created in damaged shell regions ('pearl factory') as nuclei for tiny nacreous freeform pearls, but fail to see any relation to large baroque pearls, in this case the pearls in gonad (horn) shape reputedly of gonad origin.

I'm just missing the chalkboard diagrams, I guess. Maybe we need to give it a breather. After all, the pearls are not in doubt (except for that statement about culturing conicals?).

 

[New Zealand Natural Pearl]

Hi There,
We have a conical shape in the culturing process at the moment - we will keep
you informed - a new exciting experiment for us - time will tell!!!!!!

 

[SteveM]

Hi There,
We have a conical shape in the culturing process at the moment - we will keep
you informed - a new exciting experiment for us - time will tell!!!!!!

That's very exciting, and as you work closely with Ken Scarratt at GIA it will be of special interest to know exactly how the labs would objectively determine cultured vs. natural, should you be successful!

However, it continues to appear that the term 'conical' refers to a distinct phenomenon vs. the 'horn' or 'gonadal' pearls that are the subject of this thread.

 

[New Zealand Natural Pearl]

Horn, conical, bear claw, tooth etc are all the same (gonad shape) and are terms for the
pearl which has been formed around the GONAD area -

 

[SteveM]

Thanks for the confirmation. But 'gonadal area' appears intended to counter 'in the gonad' per CIBJO:

5.79. Gonad pearl
a horn or cusp-shaped natural pearl common in abalone (5.1), formed in the similarly shaped reproductive organ or gonad (5.78).

Assuming your culturing process has the objective of creating pearls of this shape and they do not form within the confines of the organ as the gem trade is instructed to believe above, a little further clarification of how the gonadal shape is actually obtained in a living animal would be much appreciated!

I would welcome credible debunking of the concept of nacre secretion away from the mantle as suggested by these pearls. Thus my push here.