There are 17 conditions associated with discharge or mucus in eyes, drainage or pus and yellow eyes. The links below will provide you with more detailed information on these medical conditions from the WebMD Symptom Checker and help provide a better understanding of causes and treatment of these related conditions.
Burning glass. A burning glass or burning lens is a large convex lens that can concentrate the sun's rays onto a small area, heating up the area and thus resulting in ignition of the exposed surface. Burning mirrors achieve a similar effect by using reflecting surfaces to focus the light.
The major ingredient for glass making is silica, in the form of sand. Only sand of exceptional purity can be used to make glass. If the sand contains a trace of iron, for instance, the glass made with it will have a greenish color. Even for ordinary window glass, sand must be better than 99 percent pure silica, perfectly white, and not too fine. But I guess if you are looking for 4 main ingredients... Silica Sand 60% Soda Ash 20% Limestone 15% Alumina-Silicate 4% Those are the 4 main I could find. But really it's all about the sand.