pearl composition

[nima]

is there a diff in the composition between freshwater cultured pearls and salt water pearls.

[DerekJ]

Cultured Saltwater pearls will have a Mother of pearl bead nucleus with layers of nacre on top of it. Most freshwater pearls do not have this nucleus, although there are some larger freshwater pearls that are bead nucleated now.

[GemGeek]

There are different chemical elements present in sea water and freshwater rivers and ponds that make them distinguishable by laboratory tests. For instance, it is possible to tell the difference between some freshwater growing areas. With Japanese pearls grown from lake Kasumigaura and the look-alikes grown in China - one has more gallium and one has more barium, and they have different levels of strontium. Probably more information that you ever wanted to know, but it is possible to tell them apart forensically.

[KarinK]

That's really interesting GG. I didn't know it was possible to distingush between real Kasumis and the chinese look-a-likes. But if you need to smash the pearl to find out, i guess it doesn't matter mach

- Karin

[Nora]

You don't have to smash pearls. There are any number of non-destructive tests such as Energy-dispersive X-ray fluorescence (EDXRF) or Laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) to mention only two.
Yes the tests are expensive and only a few places do them.

[GemGeek]

Good point Nora. The cost would only be worthwhile on very expensive items.

[KarinK]

I'm just thinking in case someone (not me!) ends up with a museum worthy strand of Kasumis like the one Sarah is selling at Kojima Pearl, it is comforting to know that the origin can be verified if need be. I think last time we were talking about the look-a-likes (that really do look alike) the only way of knowing was provenance.

- Karin

[nima]

thankx thats quite some info.i had read that the aragonite plates in salt water pearls are more compact than those in fresh water pearls.it was written that when doing the tooth test the freshwater pearls feel more grainy or gritty than salt water pearls due to the aragonite plates being more compact .is it a fact .