The Force has facets to it like the crystals of a lightsaber. Imperfect, blemished, clarity, cut, karat, etc. The two most familiar facets are the Light Side of the Force and the dark side. The Force is all the same one piece, that binds us and holds us together in the galaxy, according to the old Obi-Wan Kenobi Jedi Master adage.
In Star Wars Rebels season 3, those facets of a crystal will shatter and the shards will scatter like sand on a beach, since most crystals are smaller components to rock and sand.
The Star Wars Show on Youtube shows a clip of Star Wars Rebels season 3 at ~3:30 minutes. It shows what it is like before the crystal breaks through the Force.
Crystals used in the Force are responsive to the Force, and emotion of the user. The crystal and the Force user connect and share some type of bond, though imperfect. How does a rock bond to a human being? A sentient being? Life?
The basis of most life is the firmament or the soil that requires key components and nutrients to grow all other life. With a diurnal variation, oxygen and water, life will grow in a season. Seasons can vary from long to short, but the point them is to have a time to exist and then there is change. The only reliable thing about life that everyone can count on is that it changes, then it dies, which is a change.
During the time of Star Wars Rebels, they are finding what their eutectic point is as young people. Things must die so that new life can be born and evolution takes place. People can think that is not fair, and game the system and many characters do in Star Wars, but the Force is an act of nature and is fickle about its domination. It shifts like the eddies of a tiny brook to a tumultuous wave.
The key is, let the Force flow…
FYI: All this is being said because Ezra’s lightsaber (visit him on Facebook) is green and where did he get the crystal? It looks like Kanan’s but it doesn’t seem like it is from him.
To understand more about the esoteric Force, read this Star Wars Legends book.