a. consisting of or containing or of the nature of crystals
Quartz is the most common form of crystalline silica.
Sentence in Classic:
Though in life it remains perfectly fluid, yet, upon exposure to the air, after death, it soon begins to concrete; sending forth beautiful crystalline shoots, as when the first thin delicate ice is just forming in water.
Moby Dick By Herman Melville Context
The thing was generally complete, but the twisted crystalline bars lay unfinished upon the bench beside some sheets of drawings, and I took one up for a better look at it.
The Time Machine By H. G. Wells Context