As far as I know, they aren't the same...but, now I'm questioning myself. There are 2 downloads that we both need to read. Under "Silica Connection" there is one for DE.
I'll stick with what I know, until I read those downloads. Silica is a natural silicon element; the herb horsetail is high in silica. DE is an enzyme and I don't remember all the components (its was 15 yrs ago that I heard of DE). Time for more homework!