Between 10k and 14k

Hi all, I am new to the whole metalworking scene and am primarily
interested in forming holloware both from silver and gold. A friend
gave me a lot of scrap gold, a mixture of mainly 14k and 10k, about
3ozt. Unfortunately he took a torch to it and melted it all together
so it is one big lump. So assuming that it is somewhere between 10k
and 14k, should I send it off to be refined into either 14k or 10k?
is there a big difference in color between the two? I plan on rolling
it out into sheet, so is there a big difference in its working
properties( I have yet to work in gold and thought it would be a
great start instead of spending a fortune on sheet without any
knowledge of it). Is it expensive to refine it? I will probably
start out making a small piece (pillbox or something) so if I were to
sell it as a holloware piece, do people usually have a preference in
karat as they seem to have in jewelry? one last question… is there
a big difference in techniques between gold and silver fabrication,
other than the higher melting point and density of the gold? any help
would be great and thanks for all the great info I receive everyday!
Mical in Michigan!

Versace@chartermi.net

Why not add enough 24k to make it 14k?it’s easy enough to tell the
karat with a scratch stone. Hope it helps! Ringman