Popcorn

Popcorn is an extreme form of flint. It has a very small proportion of soft starch. It is a very minor crop, and is gown mostly for humans to eat. The reason it "pops" so well is because of the horny endosperm, which is a tough, stretchy material that can resist the pressure of steam, which is generated in the hot kernel until it has enough force to explode or "pop."