🚀 go-pugleaf

A friend of mine is trodding down the path not normally taken, and is moving
to Fiji to farm pearls. Here's his question.

When inseminating an oyster to make a pearl, one inserts a pearl nucleus (usually 
some random spheroid made of an inert material) and a piece of mantle from another
oyster (let's call it the donor).

He says that the color and quality of pearl depends on what part of the mantle from
the donor is used in the target oyster. If you want a dark pearl, you use one part
of the oyster, if you want a different color, you use another part. 

He then launched into technical oyster-farming lingo which I didn't understand being
that I'm an astronomer. 

Anybody have any scientific justification/explaination for this?

Please reply via email as I don't normally read this newsgroup. 

Thanks

 nikjo@microsoft.com