March 8, 2005
White Gold Whiteness Index Introduced
The Manufacturing Jewelers & Suppliers of America and the World Gold Council announced the development of a White Gold Whiteness Index that, for the first time, defines color grades for white gold. The three grades are:
Grade 1: Good White. Includes alloys measuring less than 19 on the CIELab and ASTM Yellowness Index. These alloys do not require rhodium plating to look white.
Grade 2: Reasonable White. Includes alloys measuring between 19 and 24.5 on the Yellowness Index. Rhodium plating is optional.
Grade 3: Poor White (incomplete bleaching). Includes alloys measing between 24.5 and 32 on the Yellowness Index. Rhodium plating is required.
A White Gold Task Force developed the white gold definitions and colored grading system, with research by the English parent company of the American Assay & Gemological Office, the Birmingham Assay Office. Cookson Precious Metals researchers also worked on the standards. Various alloys of white gold will produce the three grades.
A template that shows seven color samples based on the three grades is available from MJSA for $145 (MJSA members) and $195 (non-members). The task force also recommends specific light sources for viewing the template accurately to judge white gold jewelry colors. Two are available from MJSA and are made by GretagMacbeth Munsell Color Assurance Laboratories, which also helped develop the White Gold Whiteness Index template. A tabletop viewing booth, SpectraLight Junior, features a box to protect the viewer from ambient light and costs $1,900. A desktop lamp called Sol-Source also features optimum north-sky daylight viewing conditions and costs $375.
The White Gold Task Force is hoping the index will be adopted worldwide by groups such as CIBJO, the international jewelry confederation. Up until now, there as been no legal definition of white gold, says Christopher Corti, director of International Technology for the World Gold Council and a central force in the development of the index. As a result, poor grades of white gold have been rhodium plated and when the plating wore off, consumers were dissatisfied with the yellowish brown look of their "white" gold jewelry, creating problems for retail jewelers.
Retailers can chose to buy the White Gold Whiteness Index kits and light sources to perform their own quality control on the white gold they buy and also to communicate the kind of white gold they wish to buy from suppliers. Or, they can have a professional lab such as the AA&GO perform the index tests.
To order kits and light sources to do testing yourself: MJSA, Providence, RI; (401) 274-3840, email@example.com.
To have testing performed for you on white gold jewelry: American Assay & Gemological Office, New York City; (800) 917-7558, firstname.lastname@example.org.
by Peggy Jo Donahue