Analysis please
Crystal is a solid that has an organized molecular structure called a crystalline lattice. As a result of this organized structure, crystals can exhibit extreme hardness - perhaps the best example of this is Diamond which ranks the highest on the mohs scale. As a crystal is defined as that which has a paticular molecular structure, virtually any organic material can be crystallized. Whether it be carbon, water or silicone. Because of the arranged molecular structure crystals typically take the form of geometric shapes.
In the Naruto world, Crystal was first demonstrated as an ability by Guren - who could produce crystals, and crystalline any physical substance - even down to a cellular level in the case of living tissue. The Release on this site is made of Earth and Wind, Earth evidently because Crystal is a common product of the earths crust. I'm honestly not sure why Wind is a component.