ForMatter/Finishes/patina/Mokume gane (laminated wood-grain metal)
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Mokume gane (laminated wood-grain metal)

patina · patinated · wood-grain metal, 木目金, Japanese laminated metal

A multi-layer billet of dissimilar metals — silver and shakudō, copper and gilding metal, palladium and white gold — diffusion-bonded into a stack, twisted / drilled / forged to expose layer cross-sections, then patinated to color each layer differently. The surface reads as polished wood grain rendered in metal. Originated in 17th-century Japanese sword fittings; carried into modern wedding-band work by Tiffany & Co. and studio metalsmiths.

Sequence: stack 8–25 thin sheets of dissimilar metals (~0.4–1.0 mm each) clamped between graphite plates; diffusion-bond at ~75% of the lowest melting point, ~20 MPa pressure, 10–30 min in reducing atmosphere or vacuum. Forge / roll / drill / grind the billet to expose layer geometry on the surface. Etch with an acid that selectively colors each metal — ferric chloride for copper, ammonium persulfate for silver, rokushō (copper acetate) for shakudō and shibuichi alloys. Modern Western work uses palladium / white-gold / red-gold combinations etched with selenium-based jewelry patinas. Repeat etch cycles intensify color and depth.

character — fluid wood-grain pattern in metal, polychrome at depth, archival, classical-Japanese register.

Finish properties

  • levelpatinated
  • subcategorylaminated billet, etched / patinated reveal
  • applies tometal

Second life

reversibilitymoderate — patinas can be stripped (acid, mechanical polishing) and re-applied; the substrate metal is preserved through the process. The historical patina cannot be exactly reproduced after stripping.
blocks substrate recyclingno
renewabilityfield-renewable — a patina can be refreshed or applied to a stripped piece by a metalsmith with the right chemistry. Conservation-grade re-patination is a specialty (Sculpture Conservation Studio practice).

Hughes & Rowe *The Colouring, Bronzing and Patination of Metals* (Crafts Council, 1991, Watson-Guptill ed. 1995); American Institute for Conservation patina-conservation guidelines.

Citations

  • url · https://en.wikipedia.org/wiki/Mokume-gane
  • book · Untracht, *Jewelry Concepts and Technology* (Doubleday, 1982), mokume gane chapter.
  • book · Midgett, *Mokume Gane: A Comprehensive Study* (Earthshine Press, 2000).