The origins of white gold date back to the 1920s, when the blend was developed as a substitute for more expensive platinum. Many white gold blends are actually closer to a rose or yellow hue, something that is often remedied by the generally undisclosed use of a rhodium plating treatment of the jewelry piece(s). This can cause problems later if the rhodium coating starts to wear thin in spots, revealing the yellower gold color beneath it.

US White Gold Ratings Guidelines 

For many years, the jewelry industry's definition of what officially constituted white gold - a blend of gold and silver alloy material such as nickel, palladium or magnesium - was nebulous. But on March 7th, 2005, at an annual New York City trade show put on by the Manufacturing Jewelers and Suppliers of America (MJSA), the organization in tandem with the World Gold Council announced a new voluntary set of U.S. definition and ratings guidelines.

White gold was defined as having a value of 32.0 or less on the Yellowness Index, an ascending scale of measurement set up by the American Society for Testing and Materials (ASTM). Within this range, three grades of white gold were also specified: Premium (a Yellowness Index count of 19.0 or less), Standard (19.0 to 24.5) and Non-white (24.5 to 32.0).

White Gold Whiteness Index 

In conjunction with this overall industry initiative, the Swizterland-based company GretagMacbeth announced the establishment of a White Gold Whiteness Index. This reference tool, intended for jewelers who do not use the advanced equipment of a spectrophotometer, allows them to determine the tier of white gold by comparing it with a naked eye chart of seven yellow gold samples.