There is no single source for good material in the US. I have found
it is like any other product you have to search out those who carry a
particular material. As an example, the Opal from Louisiana, or Blue
Jade from California, Black Jade of Wyoming, or any of the Jades of
Wyoming. The problem you are dealing with is that some of the
materials are not found in sufficient quantity to make them available
to a mass distribution, in other cases the material was sold out
years ago and the only way of finding it is to visit the local rock
shops or collectors in hopes that they have some "tucked away", most
of local rock stores do not have web sites and a visit is required.
Another thing I would suggest, research specific items you are
searching for. Find what made it desirable, and what the qualities of
good rough are for a particular specimen. In some cases I have had to
go to the state records to find claim holders, and then follow-up on
those leads to find material or dealers of the material, in some
cases the claim holder could even tell me the collectors of the
material. If you are looking for good material, there is no single
source only research, rumor and innuendo to follow up on. In the end
you may find what you seek, or you may find that the material
reported was not really what it was claimed.
Your question is like asking is there a single source for all North
American made jewelry. The answer is obviously "No", you would have
to search out a good source for Canada, Mexico and the United States.
Also, read the trade magazines, newspapers and other sources which
follow such stuff. Currently I am still trying to get a sample of the
find in Canada of Emerald, there are samples around but nothing
available to the collector yet that I have been able to find. If
anyone reading this knows of a source, would you mind letting me
know, I would really appreciate it. I don't care about the quality it
will not be used for lapidary purposes.