The best white gold is the UK and European standard. No nickel
allowed!! the Spec is 75.1%999 gold,11.85 999 silver and 13%
palladium. This is classed as he 18ct standard and is hall marking
quality The best stockist in the UK and Europe is Cookson Gold.com.
go to their web site its all there.
Now, we cannot help you more because you do not say where you live,
or what country.
What you want to make and what training or years experience you have
nor what equipment you have, or do you work for a jeweller? or are
you on your own? Do you have a web site? We need all this to reply
with anything useful.
Await your reply.