Spiny Oyster Pearl

[edrodrivaz]

Hi all.

I found this pearl of Spiny Oyster

 

[Pearl Dreams]

Goodness-- is that a flame pattern? Is this a non-nacreous pearl, then?

 

[Lagoon Island Pearls]

That is a terrific pearl!

It has an interesting spotted appearance in the flame pattern.

Spondylus sp. have really attractive shells. Although they are often called oysters, they are actually scallops (pectiniodae). Their hinges are not the typical the tooth like structures observed in other oysters and scallops, but a ball and socket instead. They also have eyes. Not retinal eyes like ours, but light sensitive organs that are able to compile a binary image. They cement themselves to the substrate as opposed to byssal threads in many others.

You certainly come up with some rare pearls!

Thank you for sharing this with us!

 

[Lagoon Island Pearls]

Is this a non-nacreous pearl, then?

Apologies for being pedantic and off-topic, but Blaire and I had an interesting discussion on this term the other day on Facebook. I've arrived at the conclusion that "non-nacreous" is a bit of a misnomer.

For all intents and purposes, nearly every mollusk is nacreous. There are exceptions. Nudibranch, octopus, squid etc, but that's because they have no shell at all.

Marketable cultured pearls as we know them are terraced aragonite, but foliated, columnar and even most calcitic structures are technically nacreous.

So if the question you are asking, is this pearl terraced aragonite? The answer would be no. If you ask is this non-nacreous? the answer would also be no, even though many non-scientists would say yes. Being a scallop, it's probably foliated aragonite.

I prefer to use the terms highly nacreous (pterioid), prismatic (clams and oysters) or calcareous (worms, corals, barnacles, though not all mollusks) to describe stuctures.

As experts, it's proper we should be mindful of correct terminology.

 

[GemGeek]

Yes, I have been coming around to Dave's viewpoint, but there is a wide world out there that is going to have a hard time breaking out of their pearl paradigm. It's so much fun to be able to hash out our ideas with people who care. Edrodrivaz, that is an outstanding pearl. How about a few more photos?

 

[pattye]

Wow, that is fascinating~more photos please and also measurement? Is it round, or button shape? Congratulations on a great find!

 

[edrodrivaz]

I agree with your comment David.

I have this photo of the shell where it was found this pearl.

 

[edrodrivaz]

Here are more photos of this pearl

 

[Lagoon Island Pearls]

I have this photo of the shell where it was found this pearl.

Scallops are beautiful in so many ways. I'm not sure how many subspecies are described, but it's a lot. Not as many as clams, but the colors, shapes and other features are extraordinary when compared. Scallops grow slow, live long and present with evolutionary features not easily seen in other mollusks, namely eyes and the ability to swim after metamorphosis (though this subspecies becomes sedentary later in life).

Baja California is a rich environment for scallop diversity and Edrodriviaz has done well to collect them.

 

[Pearl Dreams]

Fascinating, Dave, thank you for the lesson!