When I was very young I went through an aliens phase and a crystals phase at the same time. In class, we were often assigned projects in which we had to write stories, so I wrote one about an invasion of Earth by crystalloid aliens. So yes, I could imagine that aliens at one point looked like crystals. If you want to know the ending of the story, the humans are all killed during a final battle with the aliens, but their DNA is reabsorbed by bacteria at the scene, which develop into a stronger race of humans able to fight back the invaders and repel them.
Anyhow, carry on.