What is Pink?

Can you fill in the missing words?

  
What is pink? a rose is pink
the fountain’s brink.
What is red? a red
In its barley bed.
What is ? the sky is blue
Where the clouds thro’.
What is white? a swan is
Sailing in the light.
What is yellow? are yellow,
Rich and ripe and mellow.
is green? the grass is green,
With flowers between.
What is violet? clouds are
In the summer twilight.
What is orange? , an orange,
Just an orange!