Pyrite Crystal Habit distills the pre-1900 Western European tradition of crystallographic habit plates — engraved illustrations that catalogued the cubo-pyritohedron forms of iron sulfide (FeS2). Pale brass-yellow metallic crystals with striated faces and intergrown twins sit on a slate-grey rock matrix, their luster and faint tarnish iridescence rendered with engraved precision.

This system turns that mineralogical plate into a digital language: a dark mineral-gray ground lets brassy gold dominate, monospaced indices label crystallographic axes, and engraved serifs name each specimen with period authority.