News | Diamonds
White Gold Whiteness Index Introduced
You can buy white gold that won't turn yellow
By Peggy Jo Donahue
White gold can mean additional sales among customers tired of yellow gold, but it sometimes raises a problem. Customers may complain their previously white gold now looks yellowish brown, because some white gold alloys produce inferior white color and must be plated with rhodium. When the plating wears off, problems begin.
But now theres a grading standard to judge white gold against. Or if you do sell lower-quality plated white gold, you can prepare your customers for the fact their jewelry eventually will need freshening up.
Manufacturing Jewelers & Suppliers of America and the World Gold Council announced the development of a White Gold Whiteness Index at the MJSA Expo which defines color grades for white gold. Various alloys of white gold will produce the three grades, which 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 measuring 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.
A template that shows seven color samples based on the three grades is available from MJSA at $145 for MJSA members and $195 for non-members. The task force also recommends specific light sources for viewing the template accurately to judge color. Two are available from MJSA and are made by GretagMacbeth Munsell Color Assurance Laboratories, which helped develop the White Gold Whiteness Index template.
The task force hopes the index will be adopted worldwide by groups such as CIBJO, the international jewelry confederation. Up until now, there has 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.
Retailers may 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 the test: MJSA, Providence, RI; (401) 274-3840, email@example.com.
- To have the testing performed for you on white gold jewelry: American Assay & Gemological Office, New York City; (800) 917-7558, firstname.lastname@example.org.
||White gold earrings and ring are from Songa, Milan, Italy;
(39-02) 724-031, email@example.com, www.songa.it.