Glass is separated according to color: clear, brown, green. Food and beverage bottles (beer, liquor, soda, wine, jam, jelly, fruit); as well as cooking, drinking, picture and window glass; and mirrors and ceramics are recyclable in this category.
Prepare them for recycling by removing caps and rinsing clean. Caps are not recyclable.
What is it? Wikipedia says:
Glass is an amorphous (non-crystalline) solid material … The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica (SiO2) plus sodium oxide Na2O from soda ash, lime CaO, and several minor additives.