The first one is also acceptable. I looked up the CAS number, which has at least one MSDS sheet available; it comes out to be silicon dioxide. According to Wikipedia, it works as a flow agent, the amorphous state is called "glass", and is largely used as diatomaceous earth, a insecticide.
If you are not growing your own 6th generation barley and hops, you're not *really* homebrewing.
Fermenting: Real Ale, Extract Lager (with WLP830), India Pale Ale
Drinking: Pale Ale from the keg
Reason: forgot to include a word