The clock is 

as quiet as an ant,

Like a ticking time bomb.

Sharp pencils.

An orange is

As orange as the sun,

Like an orange eye.

Green bush.

A rock is 

As hard as glass,

Like a gobstopper.

Stone hard.

A knife is 

As sharp as words,

Like a piece of glass.

Crystal sharp.

A tsunami is

As strong as a volcano,

Like the blue ocean.

Strong wave.

A frog is

As green as a grape ,

Like a jumping cricket.

Jumping blob.