Rust is one of humanity's oldest pigments — red ochre (iron oxide) was used in cave paintings 70,000 years ago. The ancient Egyptians used red ochre extensively. Venetian Red (a refined iron oxide) was produced in Italy since the Renaissance. Today, synthetic iron oxide (PR101) has replaced the mined mineral for consistency.

Earthy, resilient, and time-worn. Rust speaks of age, endurance, and the patina of experience. Unlike the aggression of pure red, rust is patient — it reminds us of industrial decay, autumn earth, and the slow chemistry of time. It is simultaneously destructive and beautiful.

Rust has been reclaimed as an aesthetic — "wabi-sabi" in Japanese philosophy celebrates the beauty of impermanence and decay. The Cor-Ten steel used in Richard Serra's sculptures develops a protective rust patina. In Australian Aboriginal art, red ochre has deep spiritual significance. Industrial rust became a symbol of post-industrial decline in cities like Detroit and Sheffield.