[perlas]

Originally Posted by Richard W. Wise

Ziede, et al,

Examined the pearls under magnification. They have an appearance that differs from the freshadama strands, they have no central shadow and they dont appear pink in transmitted light. If anything the pick up a bit of veining like the green veining in our skin. However, the round ones do have a central shadow and also turn somewhat pinkish so this may be a function of the shape.

Richard,
When are the pictures coming? Everyone is interested on this thread. Thank you for sharing your observations.

Zeide,
I have seen a white, roundish, untreated pearl with high orient as you have described..like harlequin opal. However, no central shadow is present or was I mistaken? If not, then high translucency is possible in white, round pearls without having a central shadow. The pearl I saw has a greenish glow rather than pink. Most pinks I see are sunbleached.

It seems that a central shadow is more defined in sunbleached pearls than in untreated pearls.

[Zeide Erskine]

Hi Sam,

Yes, you do see the central cavity shadow better in sunbleached pearls because the UV irradiation breaks up the conchiolin into smaller bits that render the pearl more transparent. Typically the lack of central shadow is indicative of natural pearls, but you can also have cultured pearls without central shadow if they are entirely grown from donor tissue. The greenish cast most likely comes from using a bluish light source or less likely from accumulated chlorophyll which can happen when the culture pond was overfertilized.

Zeide

[Richard W. Wise]

All,
I must apoligize I completely zoned out on this. In the iddle of a major renovation of my house. Fred Ward's photos were disapointing. I posted one on a blog post: http://gemwiseblogspotcom.blogspot.c...ect-pearl.html. Fred was unable to capture the rainbow orient on Ziede's pearls. I used a couple of images we took of Black southsea and Chinese freshwater. The Tahitian shell show distinct orient.