amorfa

Amorfa is an adjective used in Spanish and in English to describe something that lacks a definite shape or long-range structural order. Etymologically, it derives from Greek elements meaning without form. In science and everyday language, it contrasts with crystalline or structured forms that exhibit regular geometric arrangement.

In materials science, an amorphous solid has atoms arranged in no long-range order, though there may be short-range order over a few atomic spacings. This lack of crystalline lattice gives amorphous materials characteristic properties such as isotropy, transparency, and often a different thermal behavior compared with crystalline counterparts. They typically do not have a sharp melting point; instead, they undergo a glass transition over a range of temperatures. Common examples include glass, many polymers, gels, and some metallic alloys that have been rapidly cooled or quenched.

In geology and mineralogy, amorphous materials include natural glasses like obsidian and certain hydrated silica forms such as opal, which are not strictly crystalline. These substances form when molten materials cool rapidly or when crystallization is hindered by the presence of water or other factors. The term can also apply to non-crystalline phases in rocks and soils.

In biology and medicine, amorphous describes structures that lack a defined shape at the microscopic level, such as amorphous deposits or granules. The word conveys a lack of orderly, well-defined form rather than a specific biological function.

In Spanish usage, amorfa (feminine) and amorfo (masculine) adapt to gender, while the general concept remains the same.