PURPOSE: To develop a color on the alloy of a noble metal at a low cost by working the alloy contg. the prescribed amount of a base metal and a binder besides the noble metal to the desired shape, washing the alloy and developing the color by oxidation.

CONSTITUTION: A noble metal 3 such as Au, Ag, Pt or Pd is blended with ≥50% base metal such as Al or Ti and a binder 5 such as Ag, Cu or B. The blended starting materials 7 are melted in a melting and refining stage 8 and the alloy 2 of the noble metal is cast. The alloy is subjected to soln. heat treatment 10 by rapid cooling from 900°C, passed through a forging stage 11 and worked 12 by rolling, pressing, sizing and machining. After the surface of the alloy is roughened 18 by a chemical or mechanical means, the alloy is degreased 20 and washed 21. An arbitrary color is then developed 16 by oxidation under heating, chemical oxidation or electrolytic oxidation and washing by water or hot water such as ultrasonic cleaning in pure water and drying are carried out.