People think glass is only man made. Most of it is but its components come from nature. The Corning Museum has a display of elements from its permanent collection that show natural glass such as volcanic glass or obsidian and sea sponges which contain silica, a component of glass. It’s an educational display, scientific even. But we need to know about these things to better understand glass. And also when someone thinks of glass as unnatural you can let them know that glass is from the earth…check out the presentation.