Glasslike

Glasslike is an adjective used to describe materials or surfaces that resemble glass in structure or appearance. In scientific usage, it denotes substances that are amorphous—lacking long-range crystalline order—and often transparent or translucent, produced by rapid cooling or quenching or by stabilization of an amorphous composition.

In geology and mineralogy, glasslike textures occur in natural glass such as obsidian that forms when molten rock is quenched rapidly, preventing crystal growth. These glasses are typically hard, brittle, and isotropic, with conchoidal fracture. Some rocks may contain small crystalline inclusions or gradually devitrify to form crystals, altering the glasslike character.

In materials science, glasslike materials include inorganic glasses such as silica glass and borosilicate glass, and organic polymer glasses like polystyrene or polycarbonate above their glass transition temperature. They share properties such as high hardness, chemical resistance, and optical clarity, but are brittle and lack long-range order. The term is also used for amorphous coatings and films produced by methods like chemical vapor deposition or sol-gel processing.

Fabricated glasslike carbon or metal alloys with amorphous structures are used in specialized applications where isotropy and corrosion resistance are desired. When heated, some glasslike materials may devitrify as crystals form, reducing transparency or changing mechanical properties.

Glasslike is mainly a descriptive term rather than a precise material class; it covers a spectrum from natural volcanic glass to synthetic amorphous solids, all sharing a non-crystalline internal structure and often glassy visual qualities.