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Originally Posted by Caitlin Williams He is correct in saying that natural pearls are composed of layer upon layer of deposits of pearly material (a combination of conchiolin glue with calcium carbonate- which is chalky, but it is changed greatly by the addition of the gluey conchiolin and you don't see the chalky stuff unless its a bad pearl.)
OK Folks, any corrections? 
I am not sure about this but Basra is mainly noted for seed pearls, so a larger one is more special. It would also be around 100 years old (at least) if a natural from Basra. |
Hi Caitlin,
Actually calcium carbonate is chalky. It is a basic building block of the outer rough layer and inner irridescent layer of a pearly mollusc shell. It's the basic building block of a pearl too. Aragonite, the fine crystalline form of calcium carbonate, makes up the interior shell of pearly molluscs, and pearls. The fine aragonite crystals glow!! Calcite is the other crystal form that can result from calcium carbonate and it makes up the pearly mollusc's external shell(not too glowy,eh?). The conchiolin is just an organic protein that acts like a glue and can affect colour, it's usually kind of milky to fairly transparent. Aragonite is harder, has a higher specific gravity and is denser than Calcite.
You are right, the scratching of a natural pearl and some other things the seller is saying is mighty weird and he doesn't seem to know much about pearls.
Sorry again Goldnugget, this is just my personal opinion.
Slraep