We need to enhance the security of this system.

This building is made of high-quality building stone.

He came forward and expressed his opinion.

My parents are good at cooking.

Five ships are anchored in the harbor.

I will be in charge of deciding where people sit at the party.

Phosphophyllite is a beautiful green mineral that is also used as jewelry.

This mineral is called bieberite, and it is very rare in the world of mineralogy.

This rock is made of alunite.

Sudoite is a green mineral that is mainly found in Japan.