speculaire

Speculaire is a term used in French with meanings tied to mirror-like reflection, and it also appears in English as the related adjective specular. In optics, specular refers to light reflections from smooth surfaces that produce a clear, image-preserving reflection. This contrasts with diffuse reflection, where light is scattered in many directions due to surface roughness. The intensity and appearance of specular reflections depend on the angle of incidence, polarization, and the micro-roughness of the surface, and are described by fundamental optical principles such as Snell’s law and the Fresnel equations. In many contexts, specular reflections are modeled in computer graphics and vision using bidirectional reflectance distribution functions and microfacet models to simulate glossy highlights.

In mineralogy and geology, the term specular is associated with specular hematite, also known as specularite. This mineral exhibits a highly reflective, metallic luster and occurs as thin, plate-like crystals. It is commonly found in hydrothermal veins and certain iron ore deposits, where its reflective surfaces can resemble metallic mirrors.

Beyond science, speculaire describes properties of highly polished or mirror-like surfaces in French-language literature and discourse. In English-language science and art, the equivalent term is specular, used to refer to mirror-like reflection, highlight rendering, and related optical phenomena.