The coolies, earth-coloured and mute, crouched reverently some twenty or thirty yards away, and the Babu, the slack of his thin gear snapping like a marking-flag in the chill breeze, stood by with an air of happy proprietorship.
Inhaling crystalline silica can lead to serious, sometimes fatal illnesses including silicosis, lung cancer, tuberculosis (in those with silicosis), and chronic obstructive pulmonary disease (COPD). In addition, silica exposure has been linked to other illnesses including renal disease and other cancers.
This is related to the glass transition temperature, which is the temperature where an amorphous solid becomes soft near its melting point or a liquid becomes brittle near its freezing point. Most glass you encounter is silicate glass, which consists mainly of silica or silicon dioxide, SiO 2. This is the type of glass you find in windows and drinking glasses. The crystalline form of this mineral is quartz. When the solid material is non-crystalline, it is a glass. You can make glass by melting silica-based sand. Natural forms of silicate glass also exist. Impurities or additional elements and compounds added to the silicate change the color and other properties of the glass.