My own memories of such things also go back to the days of high school so I am hardly a qualified chemist. I would think, however, that precisely the opposite of what you fear would take place. In Japan and other countries in areas near the sea windows are often coated with quartz and the exterior of houses are given a layer of quartz (as a silica coating) precisely because it avoids the harm that the salt water might otherwise do.
What the heck..give it a try. If you should notice pockmarks in the quartz a few years on you'll know I was wrong. Even if so, the minute quantity of quartz that you might ingest will do you no harm.