Ordinary window glass, oil bottles, wine bottles, etc., have a light green, which is the green brought by bivalent iron ion impurities contained in the raw materials of glass manufacturing. Some medicine bottles, beer bottles, soy bottles are brownish yellow, which is still caused by iron impurities, but not bivalent iron ions, but trivalent iron ions.

One of the important ingredients in beer is hops, which give beer its special bitter taste. The components in hops are light sensitive and break down under the action of ultraviolet rays in sunlight, producing unpleasant "sun odor." Colored glass bottles can reduce this reaction to a certain extent. But brown bottles work better than green ones.

There are colorless and transparent bottles of beer on the market, and the hops added in the production are treated to make glass without color, and the raw materials selected must be free of iron. However, in nature, sand, limestone, and soda ash, there will always be some iron compounds more or less. How to eliminate the green in the glass? The chemical method is to add a certain proportion of manganese dioxide to the glass slurry. Manganese dioxide is an oxidizing agent that oxidizes the green bivalent iron ions into yellow trivalent iron ions, and manganese becomes purple trivalent manganese. When yellow and purple are combined into white, the glass becomes colorless and transparent. Glass contains different metal compounds that are "dyed" in various colors. Red glass can be obtained by adding cuprous oxide. Oxidized diamond - blue glass; Chrome oxide - green glass.