different kind
to make glass you need silica (sand), soda ash and lime stone(fluxes).
Way back... like 5000 years ago, glass was invented on a beach when sailors (or surfcasters
) made a fire with seaweed and used limestone rocks to make a fire pit... when the fire got going the ash from the seaweed mixed with the sand and the limestones and in the morning the hung over sailors awoke to a pool of cold glass inside the fire pit... (or so the story goes)