WHITE GOLD

White gold is any metallic alloy with a white luster in which gold constitutes at least 37% by mass (9-carat gold in Europe).

It emerged in the mid-20th century as a cheaper and easier-to-work alternative to platinum, when the latter began to gain popularity. Due to platinum's high melting point and issues with ductility/malleability (compared to silver and gold), the so-called "white gold" was created as an alternative.

It is an interesting alloy that frequently raises many questions. In this section, I will explain in detail its history, manufacturing method, typical components, among other things.

The most logical assumption would be that white gold is an alloy of gold and silver. Every jeweler knows that copper loses its reddish color as the quantity of the metal it is alloyed with increases, although the "whitening power" of each metal varies greatly. While a typical brass alloy (copper + zinc) where zinc reaches 40% remains golden in color, just 20% nickel is enough to give copper a unique white luster, distinct even from pure nickel itself. In the case of manganese, the required amount is even less: 18%. However, no chemical element whitens copper as much as arsenic. An arsenical bronze with 2% arsenic content is practically white. Nevertheless, arsenic is no longer used due to its toxicity.

The same does not happen with gold. Even the lowest purity gold (9 karats) alloyed only with silver (the most logical option in principle) retains some of its golden tone, resulting in a final color that is not very pleasant, opaque, and has a "greenish" tint, which is not used in jewelry.

Even before Christ, in ancient Rome, an alloy of gold and silver known as electrum was known, whose standard chemical composition is 1:1 for each metal. Its color is not very striking and it has little brilliance. Let's say it simply lacks the desired appeal in these cases. Silver, despite its excellent compatibility with gold, is not the ideal whitener. 

The key to white gold is cachet. It is, more than anything, a symbol of high social status. Obviously, it is an alloy distinctly superior in that aspect to sterling silver, but... do you really know what you have on your finger, wrist, or neck? Even the best white gold is a rather dull alloy, so it is plated with other platinum group metals to enhance its luster. However, this process is perfectly applicable to an ordinary metal, such as bronze. Yes, you read that right. Bronze. I myself have had copper rings plated with rhodium that, were it not for the difference in density between copper and gold, would look exactly the same to the naked eye, for a simple reason: what you are seeing is a coating.

Any metal used in jewelry can be coated with a rhodium solution. The metal is applied diluted in a chemical solution as a surface film over the "bare" original metal by electro-deposition. In other words, it is a pure and simple plating, like tinning, chroming, nickel plating, etc. It has nothing special, beyond the extremely high price of rhodium. I understand that customers admire white gold, etc. I know people, mostly women, who show great interest in this alloy, but as I have said before, what you see when you appreciate the luster of a white gold jewel is actually a plating (usually rhodium) that wears off over time.

Personally, I would never buy white gold. If it's for the color, I prefer silver. Historically and symbolically, it has a much longer trajectory.

If I had enough capital, I would buy platinum.

White gold is a deception. It is gold, but it is a deception.

Although the metals mentioned below are the most frequently used, virtually any metal (with the obvious exception of copper) compatible with gold can be used as a whitener. 

Initially, the mixture was attempted with nickel in a gold-nickel ratio of 90:10. Nickel is a very good metal for manufacturing white gold because it increases its toughness, hardness, and, above all, gives it a superior white color to that achieved with silver. However, it is estimated that two out of ten people are allergic to this metal, and therefore it is not commonly used today. If the client does not show allergic reactions to the metal, it can be used without any problem. Like all nickel alloys, it is of high quality. Personally, I recommend it. 

Zinc is another well-known whitening agent, but its whitening power is very low, like that of tin: a greater mass quantity of zinc than nickel is required to achieve the appropriate tone, and the resulting color is usually as attractive as that obtained with a nickel mixture. The combination of silver and zinc, or nickel and zinc, is usually the most common in Spanish jewelry today. 

Manganese is a powerful whitener. It can be used to make quality white gold, although it is not used much due to the limited availability of the pure metal and its low cachet. It is a powerful whitener, like nickel, but it does not cause allergic reactions. A manganese-zinc mixture is a good alternative to the one previously described.

Manganese also increases wear resistance.

The finest white gold is made with palladium, but it is very expensive and only a few jewelers produce it. In Spain, it is difficult to find an artisan who works with palladium, as it is difficult to work with; it has a very high melting point and, compared to gold and silver, it is a scarce, publicly unfamiliar, and little-known metal. It should be noted that the high price of this metal is precisely based on its use as a whitener in the production of white gold. 

Tin, indium, bismuth (in small quantities), platinum, and even iron or cobalt can be used to whiten gold, but these are very rare and low-quality alloys.

Tin whitens little: it is only used to increase fusibility in case the resulting alloy (e.g., with manganese) is too "strong" to be easily carved or engraved.

Indium generates a color similar to that of tin. It is a "dirty" whitish, unpleasant color, and is not used.

Bismuth is a powerful whitener but its solubility in gold is very limited. It is not recommended.

Platinum can be used in small quantities. Above 10% by mass, ductility disappears, and the alloy becomes brittle. Ironically, white gold was born as an imitation of this metal.

Iron and cobalt are soluble in molten gold (even when in solid state) but are not used to make white gold per se, but rather other "colored" grades of this metal. Iron produces what is called "blue gold", while cobalt produces a matte black alloy after a controlled process of induced oxidation; however, it is difficult to produce.

Like yellow gold, white gold is relatively easy to manufacture. I will describe the methods in detail according to the alloying agents used. 

This is the original formula, fortunately not patented, so I can describe it in detail. Pure gold is used with 10% nickel, which is approximately 90% gold by mass, about 21.6 karats, but since we must round, it is closer to 22 karats. It is a tough, ductile, and malleable alloy of opaque white color. Some copper can be added to increase ductility. Silver is not recommended because it is incompatible with nickel. 

It is advisable to melt the gold first and add the alloying agents afterward. Zinc can be added in a solid state due to its low melting point, although it will release vapors (which are not toxic). Nickel has a high melting point, but it is soluble in liquid gold, even if added solid. Manganese is added directly (solid) for a simple reason: it should never be melted separately. 

Given that the quantity of alloying metals will be greater than that of gold, it is recommended to melt them together, but in an independent crucible, and then add the gold (which can be solid). 

Before adding the metals, weigh them separately for the correct manufacturing of the alloy: 

Nickel has a high melting point, zinc a moderate one. They can be added in three ways:

* Solid: Use high-purity nickel (alone or with zinc) in the form of rods, wires, shavings, etc. Avoid using metals in powder form, as they are reactive and can respond violently when hot. With metals in their solid form, this danger does not exist. Add them slowly and stir everything, dissolving them in the gold, and repeat the operation. Add gradually.

* Liquid: For low-karat golds (9k) where a large quantity is used, it is recommended to melt a nickel-zinc master alloy separately in an independent crucible and then add the gold (which can be solid).

* Mixed in Granule Form: Combine the nickel/zinc and the gold to be melted in a single crucible and heat until fusion begins. The alloy will start to take shape before the gold's melting point (around 1000°C). This is recommended for low-karat golds (9k, 10k, and 14k).

Compared to nickel and zinc, manganese is very reactive, and although it can be used in low doses for 18k high gold, I recommend always using it in conjunction with nickel, zinc, or both metals. In all cases, a prior master alloy of nickel-manganese, zinc-manganese, or nickel-zinc-manganese is required. Pure manganese (solid) can also be added to the incandescent alloy, as it will fuse easily.

Previous Master Alloy:* Melt zinc, nickel, or a mixture of both in an independent crucible and add the manganese, stirring periodically. Then add to the liquid gold.

Melt zinc, nickel, or a mixture of both in an independent crucible and add the manganese, stirring periodically. Then add to the liquid gold.

The melting point of palladium is high. I recommend adding it directly to the incandescent gold and stirring. Some silver, zinc, nickel, or even tin can be used to facilitate fusion. Nickel specifically has a great affinity for palladium as they are from the same family. Silver is not recommended as, surprisingly, it does not increase ductility. Copper does. Another curiosity is that copper will not affect the final color.

An alternative with this metal is to melt it in liquid nickel and then add it to liquid gold.

Out of 24 parts:

Gold, 20–22 parts Nickel, 4–2 parts

Also, for greater ductility:

Gold, 20 parts Nickel, 3 parts Copper, 1 part

After the previous alloy, this white gold is the hardest to polish, since the higher the gold content, the more “yellowish” the alloy will appear. However, this won’t matter because, in the end, the piece will be coated with rhodium, ruthenium, or even platinum if necessary.

Out of 24 parts:

Gold, 18 parts Nickel, 4 parts Zinc, 2 parts or alternatively, Zinc 1 part, Manganese 1 part

Gold, 18 parts Zinc, 4 parts Manganese, 2 parts

The most popular combination is made with Zinc and Silver. Nickel is rarely used because it increases the toughness of the piece too much, making it difficult to work with.

Out of 24 parts:

Gold, 14 parts Silver, 4–10 parts Zinc, 4–10 parts

The sum of Silver and Zinc must equal 10.

A small amount of Copper may be added to increase ductility, although it’s not recommended unless Nickel is used instead of Silver. Nickel is compatible with Zinc but not with Silver—keep this in mind.

This is the lowest grade of gold and one of the most popular, but be cautious with the price. Remember that by weight it’s only about 37% pure gold; the other metals, except Palladium and Silver, are scrap by comparison. Nevertheless, it’s practically impossible to know whether the alloy was made with Palladium or instead with Zinc/Nickel/Silver, which makes the decision complicated—don’t let yourself be tricked. It’s because of things like this that I dislike “white gold” so much.

Out of 24 parts:

Gold, 9 parts Silver, 5–15 parts Zinc, 5–15 parts

The sum of Silver and Zinc must total 15 parts. Silver is more noble but whitens less than Zinc. Tin may also be used but whitens very little. Manganese is compatible with both Silver and Zinc, but Nickel only with the latter—it does not alloy with Silver, so avoid mixing these two metals.

Alternatives:

Out of 24 parts:

Gold, 9 parts Silver, 5–15 parts Zinc, 5–15 parts Manganese, 2–8 parts

Use Manganese with caution as it is a powerful hardener, though it whitens perfectly.

No matter what formula is used to make “white gold,” none will resemble Platinum. Even 316L jewelry-grade steel shines more brightly. Gold is gold because it is yellow—that is its beauty, its symbolic value. I’m not trying to ruin any jeweler’s business, I’m just warning you: what you admire is a Coating.

White gold is to Platinum what Alpaca is to Silver or what Brass is to Gold itself. Always a cheaper alternative or simply easier to manufacture.

“White gold” is an opaque gold alloy plated with another metal that gives it a brilliant shine. Namely: Rhodium, Ruthenium, Palladium, Platinum, etc...

But it’s still just a plating, a coating. I hope I’ve made that clear.

When that layer wears off, the piece must be “re-coated.”