Effect

Liquid glass iridescence

View-dependent rainbow sheen like a soap bubble or oil film: hues shift with the angle and thickness, strongest near grazing edges, usually over clear glass.

Also called thin film, holographic, oil slick, soap bubble, pearlescent, iridescent

A convex lens over a dark grid with soft colour glows, with a thin-film hue band on its rim.
A convex lens over a dark grid with soft colour glows, with a thin-film hue band on its rim. (dark)

Where to use it

Use in
Decorative hero objects (orbs, AI/assistant spheres, badges, app-icon layers), selected hero states. Not for everyday chrome.
Avoid
Full-saturation rainbow fills on UI panels; iridescence behind body text; mixing it with heavy frost.

Parameters

film thickness 0.3–1.2 (normalised), strength 15–40 %, mostly in the outer half of the shape; animate slowly (8–20 s loops).

How it is built

Design tool
Angular gradient (cyan → magenta → yellow → cyan) at 20–40 % in Overlay/Color Dodge, masked to the rim region; add a soft specular.
Web
CSS: conic-gradient overlay with mix-blend-mode: overlay masked to the edge ring. WebGL: thin-film cosine palette driven by the view/normal angle and noise.
Shader, in one line
vec3 film = 0.5 + 0.5*cos(6.2831*(thickness*(1.0 - cosTheta) + vec3(0.0, 0.33, 0.67))); col = mix(col, col*film*1.4, strength * edgeFactor).