I guess you are asking about Prelude and Variation from
Raymonda ballet.
It is from Act I, tableau 1. The scene is called “Raymonda’s dreams”
and below is a youtube link with that dance:
http://www.youtube.com/watch?v=HBZRg3-YqFQ
And another video featuring a young Russian harpist performing this beautiful
harp solo:
http://www.youtube.com/watch?v=xalwwIDe1TE