(Oct 8, 2020) A lot of different things are mixed with silicon dioxide to make different kinds of glass. Added lead makes crystal. Most ordinary glass is made with the addition of soda lime. Pyrex glass has boron to give it heat resistance. Fiberglass contains aluminum. Amorphous substances like porcelain and polycarbonate plastic can also count as glass, as can certain amorphous mixtures of metal.

One of the most interesting new technologies is Bioglass, where calcium, phosphorus and other bone nutrients are added to glass to serve as a matrix for replacement bone. Actual bone cells are attracted to the glass and new, healthy bone can form around it. Martha Foley and Curt Stager discuss.