Cracks in 9ct yellow gold

Hi Folks,

I’m making a 9ct gold pendant at the moment. It’s not a metal I
usually work in (I normally use 18ct, silver or a mixture of the
two) but the size of the pendant excluded using 18ct due to cost. It
consists of a round, domed back plate to be set with a round stone
in a bezel setting. After soldering on the bezel, I noticed two
cracks that ran through both the bezel and back plate. I am aware
that one can get these sort of problems with red gold and even white
gold due to the metal being “hot short” but had not come across it in
yellow gold before. Is this likely to be the problem? I must admit, I
didn’t pay particular attention to the temperature I was quenching it
at as I generally quench in cold pickle to speed up the pickling
process (I don’t have the ventilation for hot pickle) and I had to
remove a couple of pins holding the bezel in place first. Blasted
annoying anyway. For future reference, can anyone advise me what I
should have done to avoid this?