The Creation of White Gold
9 Minute Read
White gold presents unique challenges. Who among us has not struggled with white gold at one time or another? Some of those challenges sparked an important collaboration of every level of the trade, from alloy producers who make of millions of ounces of alloy to retailers that sell millions of ounces of gold jewelry and command huge market share.
A Report from the White Gold Task Force
Fashion trends brought this odd gold to the very fore front of design and sales. White gold is odd because a popular way to bleach 24 kt yellow gold into a white 10, 14, or 18 kt is a source of allergy, manufacturing complications and color compromises. The "bleach" is nickel. Nickel is by farthe "whitener" of choice in the USA. It is also the source of the hardness and the high temperature melting points faced,by casters.
Nickel is the most common metal allergy experienced by humans. If a high release nickel alloy of any composition is left within a skin wound through the healing process (like body piercing) a person is far more likely to become allergic. The most common symptom is an eczema like rash, which can become very severe in rare cases.
In Europe, a few years ago, it was decided to regulate the "release" of nickel from any nickel-containing alloy in direct skin contact. A controversial "nickel release rate" test was devised to find this release rate for any sampled item. The allergy is a fact, there is however, debate about what to do about it. In fact, some people can get symptoms even from nickel bearing items that pass the test! This wound up encouraging the use of lower nickel alloys, which hurt the white gold color. On the other hand the vast majority of people can wear nickel alloys without any symptom at all.
To avoid the consequences of the nickel, the rare unscrupulous jeweler might rhodium plate yellow gold to fill a white gold request. A manufacturer may compromise the nickel content in their alloys to ease casting and setting. A rhodium-plating job may be cost cut into poor performance. These things can really anger a consumer who "sees red" after seeing yellow on the bottom of their still new ring, and diminishes the reputation of white gold jewelry. However, to legally claim aperson is plating over yellow one must define exactly what white is. So we have a real need for our index.
In 2000, the nickel restriction began to be enforced in Europe. The prospect of similar action in the USA sparked a roundtable discussion on white gold in general at Kraftwerks 2002. As an alloy maker and director of Kraftwerks I saw the chance to air out the issues. The Manufacturing Jewelers and Suppliers of America and the World Gold Council quickly teamed up with a broad based, but small group of interested parties. Eighteen key members including refiners, manufacturers, alloy makers, and retailers made up the White Gold Taskforce. Also invited were members from the BirminghamAssay Office in the U.K. and Art Schhmehling from GretagMacbeth.
With help from the Birmingham assay office, Cookson Precious Metals Ltd, and GretagMacbeth we found established technology to assess the true color of gold alloys. "GretagMacbeth" known to us as Munsell Color services came through with very helpful work, and Art Schhmehling deserves credit for working up the sample chart referred to later on.
The Solution and Methodology
The color technology chosen is the ASTM yellowness standard D1925. In short, we found "yellowness" was the crucial color aspect to white gold. Ordinarily a bit of gray or red is far less objectionable to the eye. The standard is complicated in a scientific or mathematical sense to most of us. Many industries and countless manufacturers internationally recognize it, and it works with the internationally recognized CIE color coordinate system.
The color of paper, food products, ink, paint, and now white gold all must be exactly measured and duplicated on demand with global reach. That is why the resulting four level system and tools are easy to understand and use.
There are three levels of white in the index. Grade One, sometimes called "premium white" is where rhodium is not necessary. The yellowness Index or "YID" is 18.9 or lower. White One has enough nickel to be very difficult to bend or set very easily, and when palladium is used rather than nickel it's expensive. In either case, the castings are done very hot which causes added polishing and weight loss. Certain "grain refined" alloys made for the most sophisticated manufacturers may provide surprising good properties. Often these do not work in less controlled conditions like torch casting or with less expensive casting equipment.
GradeTwo (standard white) contains more yellow but rhodium is still considered optional. White Two has a YID from 19.0 to 24.5. This grade white gold is in extremely common use today.
Grade Three is the real compromise. We call this "off-white". The YID range for White Three is from 24.5 to 31.9. Rhodium is required for grade three. Why use Grade Three White at all? Certain techniques can be accomplished best in grade three. Anticlastic raising for example requires a very malleable gold. The most demanding methods of chain making, setting and very sophisticated fabrication are often impossible at grade one and even grade two may be impractical. Work continues among all alloy makers to improve the performance of Grade One and Grade Two white golds. Either price, flow temperature, or malleability has driven nickel or palladium to the lowest acceptable amount when you choose off-white gold.
Any more yellowness than YID 32 and it's not white. Still perhaps very pale compared to a rich yellow but it is not white anymore. It would be deceptive to label or sell this as white gold WITH or WITHOUT plating.
To get an exact "YIDL925" measure a machine called a "spectrophotometer" is used. Munsell Lab makes these and they are sold either through Munsell or pending a sales and service arrangement through MJSA. The machine is hand held, about the size of a consumer video camera. The human eye is not used at all to judge the grade with this meter. The $8,137 price for this machine might be too expensive for smaller operation, so various locations will invest in the machine and provide testing for a fee. One of the first is the American Assay and Gemological Office.
As an alloy supplier and innovator, my employer PMWest must depend on the expensive color spectrophotometer. The individual jewelry maker will find the $409 "Sol Source" desk lamp with a single calibrated light source and the $150 Color Index chart adequate. Shine the desk lamp on the chart and the sample to see what grade the sample is. In a desperate pinch for an educated guess, the chart alone will do in good ordinary light. Do not use a very yellow light source like low wattage incandescent. This risks being fooled by the uncontrolled light you are in at the time but the chat alone beats using nothing at all.
Established companies may want to get a Gretag-Munsell light box with single or multiple light sources of calibrated properties. The cost ranges from $ 1 375 to $4562. With these, you use the Colorlndex chart, which is a series of coated foil samples on a special background that brackets the index grades. You use your eyes, the light box, and the chart with samples of white gold to judge the grade.
I found all of this equipment very useful and very clever. If you care about the color, get the chart and the bench light at a minimum. However, the less sophisticated the equipment the less exacting the results.
The color index becomes an excellent way for professional buyers working for retailers to effectively communicate with suppliers on colors. Each user of white gold can find their own blend of policies and standards. Suppliers will obtain alloys proven to meet those options, limited only by chemistry laws and price points. The buyers are in charge while alloy experts match options and opportunities.
All of the needed color evaluation equipment is being made by Munsell and distributed by MJSA exclusively. This assures consistency. It is important to note this color technology can be used to measure any color of gold, we hardly need a rose gold task force. Learning from the white index can establish how to do them all, based on established work. Imagine if diamond dealers could use this technology… However,I digress.
Suppliers, manufacturers, retailers and alloy makers can speak the very same color language to match sizing stock to casting grain. We can match cast components to die struck or machine made parts like chain. How about Earrings and earposts? Earposts and backs? All can be matched when we speak the right color language. White gold today - Someday in every color.
Compromises and Things Left Alone
What we did not do is get into rhodium performance. It is hard to correctly measure and no established test methods exist that are practical at this time. Simple thickness is far from the only factor in rhodium plating durability. Many consumers have seen so much rhodium plated white that they expect rhodium color every time they shop white gold.
Grade Three white gold needs rhodium plating with excellent adhesion and athickness calculated to provide long-term satisfaction to the customer. Anything else and we risk alienating those who love white gold.
Another set of issues deliberately left to others to consider are political positions and legislative issues. The task force has no official position on existing or imagined regulation. There is a general hope that no legislation will be necessary to address these issues, and we believe this index will help prevent litigation from frustrated buyers.
No specific color recommendation is made either. WGTF makes no suggestions as to where, when, or how to use each of the three grades of white. The color index and the related tools to measure are there for you as thejewelerto make the bestdecision foryou andyour customers.
All of this is voluntary, there is no government enforcing this index. The past couple of years of WGTF work have shown what collaboration, intelligence, and patience can do. Everyone set competitive and conflicting interests aside. Several key alloy makers and gold refiners who compete for market share all year long helped as needed with intelligence, considered opinion and understanding for other member's concerns. The retailers made their needs known and taught the rest of us how to accomplish this task without harming their market or customer confidence. Metallurgists kept us all aware of the chemistry facts and effects. The color experts changed how we all perceive light and color.
Now you know how the index was made. Conceived at a Kraftwerks round table, birthed in the cooperation of many people and now available to help all of you make the best white gold there is. It is all there to give you the tools to address your customers who are buying the best color white gold to set those D color diamonds in. The index will help to provide healthy options to the nickel sensitive retailer or consumer. This will allow the unscrupulous jeweler to be appropriately punished for deceptive business practices in white gold. Finally, yet importantly, we can keep refiners, manufacturers, and retailers on exactly the same white gold page.
Welcome to the future of excellence in white gold.
About the Author:
Daniel Ballard is Director of Kraftwerks, long time National Sales Manager for precious Metals West, a published author on things related to casting and alloys and is a member of the MJSA/WGC White Gold Task Force. Watch for the White Gold DVD from PMWest.
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