Genny,
Dave had one explanation.  Me too have photos on xtalline balls. See below.

http://stevezeva.homestead.com/files/bga002.jpg

However, in my case, it was Lead Carbonate crystals.

In earlier TN postings, I have demonstrated other similar balls from a well 
known vendor.  They did not give an explanation of why the balls looked like 
that, only that this was nothing to worry about because they had always had 
that exteriour and no customers had any problems.

Inge



--------------------------------------------------
From: "Genny Gibbard" <[log in to unmask]>
Sent: den 28 May 2010 19:52
To: <[log in to unmask]>
Subject: [TN] Crystalline solder balls

> http://ipc-technet.groupsite.com/gallery/13595
> May not get many responses on a Friday before a long weekend, but your
> ideas on what I am seeing is appreciated.
> Sorry the camera on our microscope is not great.
> This is some of what remains on a board after a BGA is removed with a
> Summit hot air rework station.
>
>> Genny
>
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