Noble Metals

Rare, noble, precious... These are adjectives you must have come across to designate certain metals, especially if you are interested in jewelry. And indeed, there is often a considerable difference - especially in terms of price - between objects made of various alloys and works of gold and silver. However, those notions are rarely explained. We will try to make it clear for you in a few lines!

While some discoveries may still remain to be made, there are seven noble metals known to this day: silver, gold and platinoids (a family that includes platinum, palladium and rhodium to name the most used in jewelry). These metals all have one extraordinary property in common: their resistance to oxidation.

Oxidation must be heard here in the primary sense of the term, in other words, a corrosion reaction that occurs in the presence of oxygen molecules. We'll pass over the intricate intricacies of the phenomenon, but some well-known examples can be mentioned: rust - which forms on ferrous metals - or verdigris, that characteristic patina of coppery objects, which gives old bronze statues such a special cachet.

Or as we said, noble metals are distinguished by their exceptional resistance to corrosion. Gold is particularly stable. Apart from rare reactions which - rest assured - will not occur in your jewelry box, it is unalterable. The chemical properties of silver are a little more complex. However, contrary to popular belief, it is also insensitive to oxygen.

This exceptional property was identified very early and led the scholars of Antiquity to classify the seven metals then known, according to a specific hierarchy. At the bottom of the scale is lead, heavy and dull, ruled by Saturn. On the opposite side is silver, associated with the Moon, the whitest and brightest of all metals, and of course gold, with its unalterable yellow, associated with the sun. This idea will be widely endorsed and disseminated by alchemical science throughout the Middle Ages and the Modern era. It is then considered that the so-called "vile" metals are bastardized forms of the noble metals and that it is possible, by various manipulations, to extract their impurities to have them transmuted into their perfect form: silver and gold.

Collection of alchemical treatises in the Latin language, origin unknown, 18th century

We must state the obvious: these metals are considered precious above all, because they are rare. Being, as we have just seen, extremely stable over time, gold and silver constituted for a long time the best means of quantifying and materializing the prosperity of men, businesses or States.

In a word, to be rich meant owning gold and silver, and when you are rich, you generally like to show it off! Particularly malleable, easy to melt and shape into various forms, these metals constitutes materials of choice for manufacturing prestigious and luxurious objects, such as, of course, jewelry!

To facilitate the circulation of this wealth, they were also turned into currencies, whose value was for a long time intrinsic, or in other words equivalent to its metallic weight. It would be too complicated to go into detail here, but it is only with the influx of resources from the Americas that currencies will gradually become fiduciary (i.e. linked to a symbolic value recognized and accepted by all).

Drachma, Gold, Origin Unoknown, Bruttium

If these elements contributed to making noble metals precious and coveted materials, this notion remains nevertheless variable. It evolved along time, availability and demand. Platinum, which owes its name to the Spanish platina ("little silver") aroused, as its name suggests, very little interest when it was imported from the New World. Indeed, it was impossible to melt at the time, and was therefore almost useless! Conversely, palladium is now highly sought after for its industrial applications, and its price currently exceeds that of gold. It remains however very dependent on this demand, and its value is volatile.

In this regard, it is difficult to predict the future! Given known reserves, silver, for example, would be currently under priced. Nevertheless, new veins can still be discovered. For some years now, NASA has been taking a close interest in the asteroid Psyche: largely made of precious metals, scientists hope its study will lead to a better understanding of the composition of our own planet. If we are still very far from being able to exploit this type of resources, it is already a important field of research, and we can easily understand that such an influx would have a considerable impact on the value of these minerals!

Silver was known since prehistoric times. If the etymology of the anglo-saxon word remains vague the Indo-European root that can be found found in the Greek argyros or the Sanskrit arjun refers to the idea of whiteness and brillance. It is indeed the whitest and shiniest of metals, as evidenced by its use in mirrors making. Insensitive to oxygen, it nevertheless reacts under the action of certain chemicals, including sulfur and chlorine (therefore be careful with swimming pools and cleaning products). The ancient Greeks associated it with the Moon as well as the goddesses Selene and Artemis. Remarkably malleable, it was widely used for making jewellery, coins or crockery in particular, because its stainless nature preserves the taste of food. It also has proven antiseptic and antibacterial properties which have led it to be considered a means of repelling evil forces, werewolves and other demoniac creatures.

Known since prehistoric times and prized for its flamboyant yellow, gold is the most unalterable of metals. This property made it a symbol of perfection, eternity and royalty. Just like silver, its name would come from an Indo-European root referring to the idea of ​​brilliance. Quite logically, it was associated by many cultures with the Sun. Until the advent of modern chemistry in the course of the 18th century, it was at the center of the concerns of alchemists who thought they could unravel the mystery of its apparent perfection: all metal was, according to them, an imperfect form of gold, and could be completed by means of various manipulations. It motivated the conquest of the New World by European settlers and was at the center of the Mexican-American war for the domination of California, where many unfortunates lost their fortunes and reason in search of it. To this day, it occupies an important role in the world economy.

This family includes seven metals: ruthenium, rhodium, palladium, osmium, iridium, platinum, and rhenium. Known to pre-Columbian civilizations who used it to shape objects by hammering, platinum is the first of these seven metals to be formally identified. We find the first mentions of it in Europe in the 16th century, following its importation by the conquistadores who named it platina (little silver). Much less malleable than the other noble metals, darker than silver, and impossible to melt down with the technologies of the time, it aroused little interest. It was not until the development of modern chemistry and the manufacture of new tools at the turn of the 19th century that its derivatives (mentioned above) and their specific properties were identified. Platinoids gradually became popular in jewelry for their robustness and resistance to tarnishing, as well as in industry (automotive and electronics in particular). As the price increases with demand, they are therefore considered precious metals.