Gold plating is the mainstream of noble metal plating used for decorative purposes. Gold known as a rare and expensive metal from ancient times has been used for Buddhist statutes and articles, weapons, and accessories for its elegant and mysterious color, glossy appearance and its long-lasting rustproof properties. Even today, gold is widely used for accessories, fittings for bags, parts of glasses, watches and interior decor items.
Gold plating looks golden brown, but to be precise, the color ranges from reddish gold to yellowish gold. This is because of the difference of alloy constituent varying from pure gold to alloy gold in the plating. [Table 1] shows the relationship between color tone and alloy constituent of gold alloy. [Table 2] lists the carat variations and corresponding gold content.

[Table 1] Color tone and alloy constituent of gold alloy

[Table 2] Gold variations by carat and gold content

In addition, gold is known for its ductile properties. Therefore, the alloy plating containing less gold (18K) called 'hard gold plating' is a popular choice for products requiring higher abrasion resistance, such as watches and accessories.
Besides gold, the noble metals generally used for decorative plating are silver, rhodium, palladium, and platinum.
Silver plating is used for various products including accessories, tableware, badges, medals, and musical instruments for its unique color tone. The aesthetic and bactericidal properties of silver are advantages for being used as tableware. The silver plating is also known to improve the tone of musical instruments like flutes. Another popular method is called 'antique silver coloring', which is an antique finish of silver plating colored by sulfide.
While adding a sense of luxury, plating made of rhodium, palladium, and platinum is also used for preventing discoloration of silver plating and improving abrasion resistance for its high degree of hardness.