The best historical tome for crystals is the book "Crystal Clear".  It lists over 50 wartime crystal providers.  It goes over the Brazil Connection, Leo Meyerson, and a whole lot more. 
Jeep K3HVG
On 04/03/2026 7:46 PM EDT hwhall--- via ARC5 <[email protected]> wrote:
 
 
Resurrecting an old thread.  But I'm fascinated by crystals. Lemme grab some popcorn! I think AF4K's old website had a list (incomplete) of manufacturers.
 
https://af4k-crystals.com/RadioCrystals-Holders-Companies-History.htm#companies
 
Wayne
WB4OGM
 
On Friday, April 3, 2026 at 05:11:52 PM MDT, Richard Knoppow via ARC5 <[email protected]> wrote:
 
    I don't know if there is a list of companies but there is certainly
a lot of historical material out there. Making good crystals was black
magic until it was discovered that synthetic crystals could be made.
Most crystal material came from Brazil and was difficult to get during
war time. A great many crystals turned out to be defective. It was then
discovered the bad ones could be crushed up and new, synthetic crystals
grown, which were nearly perfect. Other discoveries were etching and
plating. At the beginning of WW-2 making crystals was a sort of
specialized cottage industry. There had been a relatively small market,
which exploded with the requirements of the war.
    Let me see what is in my files and if I can find on-line sources.
    It is an interesting subject, somewhat akin to the discovery of how
to make optical glass (mostly by Bausch & Lomb)  and how to coat lenses.
 
On 7/30/2023 6:28 PM, Paul Thekan wrote:
I recently obtained a box of close to 800 or more FT 243 xtals ,haven't
counted them all yet, and was going through them looking for any useful
freqs on the ham bands and noticed how many different companies were
making xtals during the war. So far I've identified at least 45
companies making these xtals.
   Is there any info out there that talks about how many companies were
involved in making these xtals.
Thanks
Paul
N6FEG
 
 
______________________________________________________________
ARC5 mailing list
Home: http://mailman.qth.net/mailman/listinfo/arc5
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
 
This list hosted by: http://www.qsl.net
Please help support this email list: https://www.qsl.net/donate.html
 
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
 
______________________________________________________________
ARC5 mailing list
Home: http://mailman.qth.net/mailman/listinfo/arc5
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
 
This list hosted by: http://www.qsl.net
Please help support this email list: https://www.qsl.net/donate.html
______________________________________________________________
ARC5 mailing list
Home: http://mailman.qth.net/mailman/listinfo/arc5
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
 
This list hosted by: http://www.qsl.net
Please help support this email list: https://www.qsl.net/donate.html