When there are five individual crystals (that is, five individual genuine substances) having (up to now) grown in a solution in some given container, each individual crystal of this set finds itself in a condition or state of co-existing with four others. That is to say, such an individual happens to be in such a state. When a sixth crystal appears, then the state of our intial five crystals has changed. Each one of them now is in a state of co-existing with five other crystals. Also the newly grown crystal finds itself in such a state.
From all this it is clear that such a state is wholly extrinsic with respect to any of the crystal individuals. And the collection of grown crystals in the solution in the container is not a substance, but an aggregate of substances.