These are the bluest blueberries I have ever seen. They're almost unnaturally blue.

Source: Tatoeba

The sky today is the bluest that I've ever seen it.

Source: Tatoeba

The colour of some hydrangeas is determined by the pH value of the soil: the more acidic it is, the bluer the flowers are.

Source: Tatoeba

Ziri always wore blue trousers.

Source: Tatoeba

Inside my backpack there are many colored pens, red ones, blue ones, green ones, etc.

Source: Tatoeba

Both girls have blue eyes.

Source: Tatoeba

He always wears blue shirts.

Source: Tatoeba

Some of the bluest water in the world is found in Crater Lake.

Source: Tatoeba

We all know that blue-eyed red-heads are sensitive to sunshine, burning more readily than dark-skinned people.

Source: Tatoeba

How blue the sky is!

Source: Tatoeba