plaster of paris,chalk,marble dust n similar material

how to use these kind of materials to make scruptures,or paintins for decoration.anybody having this tpe of knowledge,please help me.i want to make some paintings having quality n fineness n smoothness

These are all fillers that can be added into a carrier system like a resin - at varying ratios depending on the requirements you need for flow, etc...
Are you casting into a mold?

yes,can u tell me the ratio.

it depends on what sort of performance you require for your application; if you add a lot of filler into a carrier, the carrier will get thicker and not pour as easily.

on a volumetric basis, I suggest trying 1 part resin : 1 part powder to see how that flows - it depends on what type of resin you are using too.

i would premix the filler into one part of the resin thoroughly first prior to adding the other; this way you will get a better blend of the 'ingredients'.