I work with fused silica or vitreous quartz all the tim […]
I work with fused silica or vitreous quartz all the time as it takes a high temperature and has a very low thermal expansion coefficient. It is more transparent to IR and UV than regular glass. But I work in a lab as a materials scientist and need the special properties of fused quartz. I know of no common, everyday , household places it might be used. Certainly not any objects made entirely of fused quartz because it would be too expensive to make for home use and certainly not for decorative purposes. Household temperatures, even in the stove, are not high enough to justify fused quarts when there is borosilicate glass or Pyrex, or Pyroceram not seen so much lately.
Windows in furnaces (boilers, heating furnaces) were made from mica and no need for the fused quartz even in olden days. It is only worthwhile for scientific purposes or industrial equipment for high temperatures like the window for my vacuum chamber. It is stronger than plain or window glass like pickle jars or home mirrors. It is stronger than leaded glass used to make glass crystal servingware or chandeliers. It is stronger than Pyrex or borosilicate glass and can take much higher temperatures than those. Don’t forget quartz glass is fused quartz but not the same as quartz which is a crystalline material that is more likely to be found in a home in electronics or likely as a decoration as a mineral crystal. Except for electronic quartz crystals used for timing circuits or piezo ultrasonic drivers, crystal quartz is mostly decorative.