How do I make Silicone Dioxide from "100% Pure Silicone" tubes from the hardware store?

I just add two parts oxygen, one part silicone in a jar, and shake vigorously, right? (I m just kidding, hehe chemistry joke...)

I would let the silicone dry/cure so the solvent was gone, leaving "100% Pure Silicone." How do I convert this pure silicone into silicone dioxide? I am not a chemist, I am a gardener; So I do not have a laboratory, just a kitchen and a garage.

The final product need to be a powder.

I eagerly look forward to any answers!

Marshall