What would a native Romanian speaker understand this as meaning? Is it saying that the chalk is not very heavy? Or that it is soft? Or smooth? The English doesn't sound very natural to me.
Indeed :-) I think the feeling that the English is unnatural may come partly from the 'natural' ordering of adjectives, which a native speaker knows without knowing how they know. Assuming that I ever said anything as banal as this, I'd probably say that the chalk is light and white rather than the other way around.