I can't say I understood all that. What kind of silicates are available for this?

Potassium silicate is the one most often mentioned.

See Mike Rivers post (and others) in the thread linked to below:

http://forums2.gardenweb.com/forums/load/roses/msg030010308429.html

Here is a link that might be useful: earlier silicate thread

The other day I was watching a Nature Channel TV program. Apparently there was (is) a valley near Yellowstone Park where the grass has a high concentration of silicates. Over the centuries the buffalo have learned to avoid that valley (unless near starvation) as the grass very quickly wears down their teeth. I tried Googling the information but apparently did not find the correct combination to get a hit.