Large blister pearl

[olmander]

Hi everybody,

In search for an enchancer for my newly produced long grey necklace I came across a brooche with a very big (30 mm) blister pearl.

I wonder if these pearls are salt-water or FW ones. Does anybody know from what sort of mollusk or oyster it may come?

And a more practical question: I don't think I keep it as a brooche, it has such a nice luster and colour that it is worse making a ring with this pearl. Any ideas about designs for large blister pearl rings?

Olga

Her are the photos (it is not that blue as on the picture, rather lavender-greyish):

 

[Slraep]

This is dyed opercula.

Slraep

 

[olmander]

Sorry, I am not an expert - what is opercula? Is it the name of a mollusc?

 

[Slraep]

Oops, details, details, sorry it's operculum(plural: operculi) or osmena. A piece of specially secreted shell that is domed and blocks the entranceway to a gastropod's soft body tissue when that tissue is retracted. Pretty much like a trap door---keeps moisture in while keeping predators out. It must also have some other brilliant technological use for a gastropod that we humans are yet stupid about.

Slraep

 

[jshepherd]

It is also called turban snail shell or cat's eye.

 

[olmander]

I pretend I understand..
But from what sort of shell it is? Oyster? Looks too big for a FW one but maybe I am wrong.

Although this is from a rgular Chinese shop, I would guess that this is a river one or not?

 

[Slraep]

I pretend I understand..
But from what sort of shell it is? Oyster? Looks too big for a FW one but maybe I am wrong.

Although this is from a rgular Chinese shop, I would guess that this is a river one or not?

Hi olmander,

Alright! Pretend this---it's from a big gastropod. Usually saltwater.

Slraep

 

[Caitlin]

Hi Olmander

Osmena aka osmina comes from a nautilus shell. Your osmena is blue as are many of them. I don't know why they don't come in any colors but white and blue. I think slraep is correct when she says it dyed.

 

[olmander]

Oh good! I googled haliotis out, it is all clear now. Thank you for help!

 

[Slraep]

It has not really been discussed on the pearl forum, but the operculum has a fascinating makeup....

"The operculum is not a product of the mantle. It is produced by a separate organ, the opercular disc, a pad of specialized secretory epithelial cells located right where the operculum is attached - on the posterior, dorsal aspect of the foot. The opercs of some species are secreted spirally, with new material being deposited on one edge only, and the operc gradually rotating on the opercular disc as it grows. Others are secreted concentrically, with new conchiolin being deposited on all edges of the operculum simultaneously, without rotation of the operc."

Slraep

 

[olmander]

This is indeed something comletely new to me - very interesting! I am digging on Google - looks really fascinating!

 

[olmander]

It stands that haliotis has something to do with abalone shells, or is at least from the abalone family - do I see it right?

 

[Slraep]

Cat's eye comes from the Turbo species: Indo-Pacific Turbo petholatus

Other operculum can come from:

South African Turbo sarmaticus
Green Turban Turbo marmoratus
Turbo argyrostoma(small)
Turbo rugosum

Slraep

 

[olmander]

Thanks! I am going to dig further for these new ones...

Olga

 

[Slraep]

It stands that haliotis has something to do with abalone shells, or is at least from the abalone family - do I see it right?

Abalone is a type of snail or Haliotis. But the ones with operculi are the ones that are turban shaped(twisty).

Slraep

 

[Slraep]

Osmena aka osmina comes from a nautilus shell. Your osmena is blue as are many of them. I don't know why they don't come in any colors but white and blue. I think slraep is correct when she says it dyed.

Hi Caitlin,

Probably from a chambered nautilus, as you say, due to its concentric construction.

The Pacific Cat's Eye(Turbo p.) is suppose to come in natural coulours like green, peach and white, but you can see a distinct spiral construction to it, so it is not what olmander shows in her pic. The green turbo operculi were very prized by ancient peoples. I suspect the chambered nautilus operculum in olmander's pic is dyed because the blue/grey dye makes it look like it could pass as a real mabe from a dark lipped oyster, to the uninformed. Can't be 100% sure, though.

These are "cat's eye" operculum. See the spiral? Hmm...Shiva's eye, eh?

http://www.shiva-eye.com/





Slraep

 

[olmander]

Cat's eye seems to be in a different colour range
Here it is (from wikipedia)

About haliotis I found this:
"Abalones are also called ear-shells, haliotis, sea-ears and Venus's-ears, as well as muttonfish or muttonshells in Australia, ormer in Jersey and Guernsey, perlemoen in South Africa and pāua in New Zealand."

And the picture looks more in the direction of my colours:

 

[Caitlin]

Yours is definitely not haliotus. It is osmena, which is often sold on eBay as Mabe pearl and even blister pearl. I have several osmena pieces and we have discussed it in some other threads. This thread is the first time the more scientific definitons have been discussed. Thanks Slreap.

 

[Slraep]

Sorry, olmander yours is no way near abalone and not a turban shell operculum. It's a dyed chambered nautilus operculum or osmena.

Slraep

 

[Slraep]

Cat's eye seems to be in a different colour range
Here it is (from wikipedia)

Yes I know, olmander. That's why I put up a pic and website of the the cat's eye because it is different from yours. Because I want to illustrate the difference between a cat's eye operculum and nautilus osmena .

Actually(and I just found this out!!), the osmena is NOT an operculum, but an inner layer of shell from the chambered nautilus. It's a MOCK operculum!! This inner shell is usually white with some irridescence and is not completely smooth(has ridges). It does not naturally come in blue!!

Geez, the things this forum forces you to look up and study!


Slraep