Light is an electromagnetic wave, just like radio waves. The frequency of the electromagnetic wave is what determines whether you can see it with your bare eyes (like sunlight) or use it on your cellphone (radio waves). The light you can see is only a small range of the many possible frequencies electromagnetic waves can have, and your perception of different color (violet, red, orange,…) is because of their different frequencies.

The question is very interesting. How can light bounce of mirrors/objects as if nothing has happened to it? Since light is an electromagnetic wave, it interacts with objects/materials which have electrons inside them. When light hits a mirror, the electrons of the mirror move up and down according to the frequency of light. And what do electrons or charged particles moving up and down do? They emit electromagnetic waves! (or light!)

If the electrons in the material respond fast enough to the frequency of light, you get the same frequency of light reflected back. This is how a metallic surface “reflects” visible light. A mirror is usually made of Silver covered with glass. You may ask then, why are some materials transparent then? Because the electrons in these materials do not see the visible light hitting them and just let them pass through. There is an entire field of fascinating physics dedicated to the interaction of light with matter.

The speed of light in vacuum/air is the same for all colors and electromagnetic waves; the frequency of light is what determines how powerful or energetic those waves are. X-rays can have very high frequencies or high energies that they pass through human body tissue, but your bones block them. You might have seen an X-ray scan.

If a light beam is very intense (like a powerful laser), then yes it can destroy the material because of the large amount of energy hitting the object within a very short span of time.