Hi Blue.
Normally when using spirit stains on turning you really need the right surface to get the effect. ie - The wood must have the grain effects already there to be effective. The stain won't do it on its own.
If you want the marble effect you would use the wood from a branch crotch of a Sycamore, Birch, or Horse Chestnut. All pale woods, and being crotch wood will have the swirling twisted grain effect of the triple junction. Once you have prepared the surface, you go over it with say a dark blue stain. Then sand it back until you are removing some of the stained covering. Usually this would come off from the harder sections of the grain structure.
Then you could use say a mid green around the bared areas. Just stippling it on with a cloth pad. Sand it again gently this time, and you could then use yellow on any pale areas. When finished it sometimes helps to blend in the edges of the stain areas using a cloth dampened with thinners. Then you can seal with oil or spray lacquer.
As said already if you want a imitation marble, the only real way to my knowledge is using paints and sponges. You should be able to find out about this in any DIY store that deals with decorating materials.