Read the given statements and conclusions carefully. Assuming that the information given in the statements is true, even if it appears to be at variance with commonly known facts, decide which of the given conclusions logically follow(s) from the statements.

Statements:

Some gems are stones.

Some gems are rocks.

All rocks are diamonds.

Conclusions:

I. Some diamonds are rocks.

II. Some stones are rocks.

III. Some gems are diamonds.