Simplify the following text for a Grade 10 native English-speaking person.
Original: Primary nucleation is the initial formation of a crystal where there are no other crystals present or where , if there are crystals present in the system , they do not have any influence on the process .
Simplified: It is the growth of a new crystal , which in turn causes secondary nucleation - the final stage ( if removal of the crystals is not an issue ) . Secondary nucleation requires existing crystals to perpetuate crystal growth .