The complexity of their forging is notable: pure platinum already presents considerable resistance to mechanical work due to its high melting point (≈1,768 °C) and limited malleability. Introducing iridium, whose hardness and thermal resistance are even greater, significantly increases the difficulty of shaping, requiring advanced techniques and specialized equipment. For this reason, approximately nine out of ten rings made with this alloy are produced in high-temperature furnaces specifically designed to handle refractory metals, where parameters such as the melting atmosphere and cooling rate are controlled to prevent cracks or deformations.

Despite their prestige, these alloys are rarely used in artisanal jewelry. Their manipulation demands not only advanced metallurgical knowledge but also tools that exceed the capabilities of conventional workshops. It doesn't matter if it's Europe, Asia, or America: the presence of platinum–iridium in handmade pieces is exceptional, reinforcing their exclusive nature and reserving them for the most prestigious jewelry houses in the world.

With a purity expressed in thousandths—950 ‰, similar to sterling silver—this alloy has established itself as the most commercialized within the platinum segment, especially in the industrial production of high-end jewelry. However, its presence in artisanal jewelry is scarce. The reason is technical: iridium, while providing a significant improvement in surface hardness (scratch resistance) and material toughness, also introduces considerable difficulty in its manipulation. Above 5% by mass, the alloy becomes practically impossible to work by hand, even under controlled heat conditions, due to its extreme rigidity and fragility.

Even jewelers specializing in platinum often opt for other, less demanding combinations, as iridium, besides being one of the world's most expensive metals, presents a hardness that complicates processes such as rolling, soldering, or resizing. Even so, this alloy allows for modifications—such as ring enlargements or reductions—but the procedure is delicate, laborious, and requires precision instruments. The cost associated with these pieces is high: a wedding band barely 3 mm wide can easily exceed €2.000, reflecting not only the intrinsic value of the material but also the complexity of its manufacture.

This alloy is not simply a precious metal; it is a work of metallurgical engineering that embodies excellence, exclusivity, and legacy.

This alloy is not designed for artisanal work. Its manipulation requires high-precision industrial machinery, capable of exerting controlled pressures and temperatures to allow its shaping without fractures. Therefore, its use is almost exclusively limited to the mass production of wedding bands and jewelry pieces that require extreme durability and impeccable aesthetics. The finish it offers is a deep, stable white, with wear resistance that far surpasses other platinum variants, making it an ideal choice for those seeking jewelry that remains unaltered over time.

However, its beauty is accompanied by a technical complexity that few workshops are willing—or capable—of assuming. This alloy represents the meeting point between precision engineering and the most demanding luxury, where the nobility of platinum is reinforced by the tenacity of iridium, resulting in a metal that does not bend, not even under fire.

The universal kilogram standard is a piece that can be seen in a Paris museum with this chemical composition. It was chosen because of its unparalleled resistance to corrosion.

Alloys composed of platinum and ruthenium, in proportions of 90%–10% and 95%–5% respectively, offer a valuable technical alternative within the world of noble metals. Although both formulas present similar properties, the difference in ruthenium concentration directly influences the material's hardness, rigidity, and workability. Ruthenium, belonging to the same chemical group as platinum, is characterized by its extreme hardness and brittleness, qualities which, when incorporated into platinum, significantly increase its mechanical resistance without perceptibly altering its color or chemical behavior.

Visually, these alloys are practically indistinguishable from platinum-iridium alloys: they maintain the deep, stable metallic white, with a slightly lower density and a theoretically more accessible cost. This is because ruthenium is the most economical member of the platinum group, and also easier to obtain industrially. Its melting point, reaching 2,334°C, makes it an extreme-behaving metal, and its incorporation into platinum is achieved through controlled chemical fusion, where ruthenium dissolves in the incandescent mass of platinum, generating a homogeneous and stable structure.

Although these alloys remain expensive—like any platinum-based combination—their corrosion resistance is outstanding, making them ideal for applications where durability and chemical inertness are essential. As with platinum-iridium alloys, ruthenium variants exhibit exceptional wear resistance, remaining intact against scratches, deformations, and external agents. This technical nobility, combined with relative accessibility, makes platinum-ruthenium a strategic option for the production of high-end jewelry, especially in industrial contexts requiring precision, longevity, and uncompromising aesthetics.

The alloy composed of 90% platinum and 10% cobalt represents a more accessible and versatile metallurgical solution within the world of noble metals. Compared to demanding combinations with iridium or ruthenium, this formula is considerably easier to manufacture, which has favored its adoption by jewelers who work on commission with platinum. In fact, it is common for it to be supplemented with small amounts of copper, seeking a balance between hardness, malleability, and cost.

Cobalt, belonging to the iron family, acts as a hardener in this alloy, just as copper does in gold. Its melting point—much more "mundane" than the 2,334°C of ruthenium or the 2,410°C of iridium—facilitates its incorporation into platinum in conventional fusion processes. Being a base metal, easily obtainable and low cost, its inclusion allows maintaining the nobility of platinum without incurring the high prices implied by other group elements. Although marginal in terms of prestige, cobalt plays an essential role: increasing the toughness and hardness of the piece, making it suitable for daily use without showing signs of wear even after decades of exposure.

A curious characteristic of this alloy is the presence of slight ferromagnetism, perceptible despite the low cobalt content. This phenomenon, although it does not affect its behavior in jewelry, adds an interesting technical dimension. The Platinum-Cobalt 90:10 alloy is very popular in Asia—especially in Japan—and in Central Europe, where its presence is common in jewelers in Germany, thanks to its balance of strength, aesthetics, and ease of manufacture.

While it does not reach the level of sophistication of the Platinum-Iridium combination, its corrosion resistance remains excellent, guaranteeing comparable longevity. As a trade-off, the final shine of the piece is slightly lower, an acceptable sacrifice for those who prioritize functionality, durability, and economy without renouncing the noble character of platinum. This alloy embodies practical elegance: a piece of jewelry designed to accompany daily life with discreet distinction.

The alloy composed of 95% platinum and 5% cobalt is presented as an easy-to-manipulate option within the spectrum of noble metals, especially when compared to demanding combinations that include iridium or ruthenium. Its workability is notable: it allows for forging, welding, and setting processes with relative simplicity, making it an attractive candidate for jewelers looking for a less technically challenging alternative.

However, this ease of work comes with a significant drawback: the alloy lacks sufficient hardness to be used on a large scale in pieces requiring prolonged wear resistance. The reduced cobalt content—although it acts as a hardener—fails to impart to platinum the necessary toughness to withstand intensive use without showing signs of deterioration. Therefore, its application in high-end jewelry is limited, and its popularity within the sector is low.

Despite its chemical nobility and excellent corrosion resistance—properties inherent to platinum—this alloy does not meet the durability standards demanded by industrial production or by consumers seeking pieces for daily use. Its finish, although correct, does not possess the deep luster or structural solidity of other more robust combinations, which relegates it to a secondary role in contemporary jewelry design. In short, it is an alloy that prioritizes ease of manufacture over resistance and finds its place in specific niches where aesthetics and economy outweigh longevity.

The alloy composed of a minimum of 90% platinum, between 5% and 8% cobalt, and 2% copper represents, without a doubt, the most widespread formula in artisan jewelry that uses platinum as a base. This combination not only guarantees a high purity of the noble metal but also optimizes its mechanical and aesthetic properties. Platinum (Pt), present in at least 90%, provides the characteristic deep, elegant grayish-white tone that distinguishes it from other precious metals. Copper (Cu), limited to 2%, is incorporated with the purpose of improving the machinability of the material, facilitating the work of artisans without compromising the structural integrity of the piece. For its part, cobalt (Co), whose proportion can range between 5% and 8%, acts as a hardening agent, conferring moderate but sufficient rigidity to the alloy to resist daily wear for decades. A particularly balanced and recommended proportion consists of 95 parts platinum, 3 parts cobalt, and 2 parts copper, a formula that maintains the color of pure platinum intact and offers exceptional durability. This alloy is very popular in countries with a refined jewelry tradition, such as Germany, where both its resistance and its sober, timeless aesthetics are valued. 

Although platinum (Pt) is mostly used in combination with metals such as cobalt, copper, or iridium for jewelry applications, other possible alloys exist that, while technically viable, have limitations that restrict their use in this field. Among the elements that can be alloyed with platinum are rhodium (Rh), palladium (Pd), silver (Ag), gold (Au), iron (Fe), nickel (Ni), osmium (Os), rhenium (Re), tungsten (W), and tantalum (Ta), although most of these combinations have not managed to consolidate in the jewelry industry for economic, technical, or metallurgical behavior reasons.

Rhodium, for example, allows the manufacture of certain grades of platinum with interesting properties, but its high cost and lack of significant advantages over ruthenium (Ru), which is considerably more economical, make its use marginal. Palladium, for its part, does not provide substantial improvements in the hardness of the alloy, which limits its practical application in jewelry. In the case of silver, it is marketed under the name "sterling platinum," although it is actually a silver alloy with a small percentage of platinum, closer to a marketing strategy than an effective technical solution, as its manufacture is complex and the quality-price ratio is unattractive.

The combination of platinum with gold, although it may seem promising due to the nobility of both metals, generates a counterproductive effect: gold tends to embrittle the structure of platinum, reducing its hardness and compromising its mechanical resistance. In contrast, the iron alloy is easy to produce and bears similarities to that of cobalt, but its low popularity could be due to the formation of pores during the casting process. This alloy presents a gamma (γ) structure, that is, austenitic, which gives it great toughness, although it has not achieved significant market acceptance.

Nickel, when alloyed with platinum, results in an extremely ductile and malleable material, but with insufficient hardness for jewelry applications. Its use is only considered when it is desired to counteract the rigidity caused by high percentages (above 10%) of iridium or ruthenium, although in such cases copper is usually preferred for its better performance. Osmium, on the other hand, generates an alloy comparable to that of platinum with iridium, but its toxicity—especially due to the vapors it emits during hot working—excludes it from jewelry. It is used in demanding industrial applications, such as pen nibs or components subjected to extreme wear, and its proportion in the alloy rarely exceeds 10%. Its presence increases rigidity, but decreases ductility and malleability.

Rhenium can form alloys with platinum, although its use is practically non-existent in jewelry. The same applies to tungsten and tantalum: although it is technically possible to combine them with platinum, their high reactivity and the extreme rigidity they impart to the final material make them unsuitable for pieces that require workability and comfort. These alloys are reserved for sectors where exceptional mechanical properties are required, such as in aerospace components or devices subjected to extreme conditions, but they have no place in the delicate universe of platinum jewelry.

The history of platinum (Pt) and white gold (Au) has been intertwined since the latter was conceived as a more economical alternative to the former. Despite their visual similarity, many people tend to confuse them, even thinking that platinum is simply a variety of white gold due to its high price and noble character. Nothing could be further from the truth: platinum is a chemical element with unique properties, while white gold is an alloy designed to imitate its appearance.

White gold was born as a practical solution to facilitate the manufacture of jewelry that, with platinum, would be technically more complex or directly unfeasible. Gold alloys are considerably easier to work with than any grade of platinum, partly thanks to their lower melting point (1,064°C versus 1,768°C for platinum), which allows practically any jeweler to manipulate it without the need for specialized equipment. In contrast, platinum requires greater skill, specific tools, and technical experience, which limits its use to more prepared workshops.

From the artisan's point of view, white gold is usually the preferred option due to its ease of work and versatility, but this does not imply that it is superior to platinum. In fact, white gold emerged as an alternative to platinum, not as an improved replacement. When purchasing a platinum jewel, the buyer is obtaining a piece entirely composed of this noble metal. In contrast, when buying white gold, what is actually acquired is an alloy of gold with whitening metals such as manganese (Mn), nickel (Ni), zinc (Zn), tin (Sn), silver (Ag), among others. When palladium (Pd), belonging to the same group as platinum, is used, a higher quality alloy is obtained, although without achieving the natural luster of platinum.

It is important to note that the characteristic shine of white gold does not come from the gold or its alloying metals, but from the superficial rhodium plating (Rh) applied to improve its appearance. This coating, although aesthetically attractive, wears off over time and requires periodic maintenance. Platinum, on the contrary, does not need any kind of plating: its color, shine, and resistance are inherent to the metal itself.

For all these reasons, if what is sought is a durable, authentic, and undeniably noble piece of jewelry, platinum is the most suitable choice, even if its price is higher. Personally, I would never opt for a white gold ring. I prefer the warm, natural tone of yellow gold in its 18K or 14K grades, and I even value the aesthetic honesty of sterling silver more than the artificial appearance of so-called "white gold."