Do take into account there is in no way any proof in this that the water is healthier or will bring good fortune if it's listened to classical music.

What his experiments proved is that under certain specific wavelengths of sound, the structure of water is more organized.

Under the influence of sounds that are more "chaotic" like Rock music, the water's structure will be more chaotic and disorganized.

This is no way provides a causal relationship between MUSIC and how healthy the water is.

What it does is provide proof that water's structure can be changed by submitting it to different kinds of sounds.

The fact there's a difference between Rock and Classical is just related to how the wavelengths of those kinds of music are.

I'd hypothesize that Rock music (and any kind of noise in the same kind of tonality and rhythm) probably disrupts the formation of the hydrogen bonds between water molecules enough for the crystallization process to be as "negative" as seen in the picture, while Classical doesn't have any effect, or even aids the formation of "proper" crystals.