Link many attributes in one table to one attribute in another??

Hello all,

I am fairly new at db design, I have built a few simple in the past and have
never dealt with this type of problem before, any help would be appreciated.

I have three attributes in one table that should reference one, and only
one, attribute in another table. Here's an analogy of the problem:

I have a table with a list of marbles, each marble has three colors in it
(color1, color2, color3) and a serial number. In another table I have eight
colors to choose from but the list of colors grows regularly.
How do I associate a marble with three colors from the color table (a marble
may have three red sides or red-yellow-blue)?

Thanks,
Christian