i have a crystal-ly quot;quartz-likequot; rock. purples, red and white thin strpe thru it, some dark purples some alsmost clear...I thought it was glass, but antique dealer said not man made...i can't find a website that show this kind of rock...anybody a quot;ROCK_HOUND?quot;
Quartz is SiO2. Glass is mainly silica, SiO4, but has many possible additives, depending on the qualities you want the glass to have. Lead, Pb, is added for clarity, for example. Boron silicate added for resistance to snapping due to heating and cooling. And so on.
