His name was recorded in the official record.

He recorded that fact in the official record.

He decided to join the vigilante group.

He is protecting the town as a vigilante.

In order to protect the safety of the town, we organized a vigilante group.

This rock contains a lot of silica.

He was deeply thinking about the physical world.

This rock was formed through the process of silicification.

This fossil has been silicified over millions of years.

This immature fatty salmon is very rare and valuable.