In the world of jewellery, few metals have as much cultural and historical significance as ruthenium. This metal is a member of the platinum group and its properties make it a very valuable commodity in an industry where quality matters.
Ruthenium is a very durable, scratch-resistant, and strong metal that’s perfect for adding some unique finishes to silver jewellery. It is a rare and valuable metal that is commonly used in the making of jewelry, electrical connections, and solar cells.
What Is Ruthenium?
Ruthenium is a chemical element represented by the symbol Ru on the periodic table of elements.
The Ru atomic number (i.e., the number of protons in each atom) is 44 and its relative atomic mass (i.e., the total number of protons + neutrons in an atom) is 101.07.
Ruthenium is a very rare element in nature, with an estimated abundance of 0.001 parts per million in the earth’s crust. It generally occurs in a pure elemental form alongside other metal elements such as platinum and iridium, or as a component of certain minerals.
The regions in which this element occurs and is mined are in the continents of North and South America, as well as in South Africa. The annual global production of this element is calculated to be around 12 tonnes.
Some important physical properties of this element include:
- The melting point of ruthenium is 2333 degrees Celsius
- The boiling point of ruthenium is 4147 degrees Celsius
- The density of ruthenium is 12.1 grams per cm3
- Appearance: The ruthenium color is described as silvery. Specifically, it occurs as a shiny, solid metal at room temperature
- Odor and taste: Unknown
- Common oxidation states: +2, +3, +4
- Isotopes: 7 stable isotopes, with atomic masses ranging from 96 to 104
Sources of Ruthenium
- The face-centered cubic crystal structure of ruthenium is shown in the image below. When it’s as single crystals or grains, it’s both hard and ductile.
- It’s quite soft, but it can be brittle if accompanied by other metals such as platinum group elements (pgms).
- The high liquidus temperature prevents the development of self-forming lamellar intergrowths, which can cause cleavage flaws on twinning surfaces during alloying procedures.
- To be used in a commercial setting, it must be produced using a sophisticated chemical procedure.
- The final step is the reduction of ammonium ruthenium chloride to a powder, which is achieved by hydrogen. The mixture is then compacted.
Because of its low abundance in nature, ruthenium is considered a very rare metal element. However, despite its rarity, there are an increasing number of industrial and commercial uses of this element. The following sections will explore some of the most important ruthenium uses in greater detail.
These include its use in industries such as jewellery, electronics, solar power, and chemicals. One of the most efficient methods to harden platinum and palladium is adding ruthenium. It’s mixed with these metals to create electrical conductors that are highly resistant to wear.
At 10.6 K (-440.6 F / -262.5 C), a ruthenium-molybdenum alloy is said to be superconductive. Adding 0.1 percent ruthenium to titanium boosts its corrosion resistance by a hundredfold. H2S is a highly corrosive gas that causes steel to corrode when it comes into contact with water. When that happens, the steel must be removed for the process to continue.
Ruthenium in Jewellery Making
Ruthenium on its own is not generally used to produce jewelry, due to its rarity, high melting point, and brittle nature. However, this metal still plays an important role in jewellery manufacturing. Specifically, metal alloys are made by mixing small amounts of ruthenium with other precious metals such as platinum and palladium. When even a small amount of ruthenium is mixed with these metals the resulting alloy is much harder and stronger. This alloy is then used to produce pieces of jewelry that are more durable and damage-resistant.
Platinum with just 5% ruthenium is considerably more difficult than platinum alone.
It is the most difficult of all platinum alloys! Because putting a gemstone in it is so difficult, this alloy is only suggested for diamond settings by jewelers. The amount of force used may damage other stones.
What kind of setting is this?
- It has a darker tone than traditional platinum settings, to say the least.
- It’s also more difficult to harm the jewellery because it doesn’t scratch or bend readily.
Palladium and ruthenium are used in the alloy of some jewelry. This alloy is frequently utilized to make jewelry that appears like platinum without having a hefty cost. Palladium alloys are less expensive than platinum or gold because palladium is a cheaper metal. Because it is highly scratch-resistant, the ruthenium alloy of palladium is very beautiful.
Features of Ruthenium in Jewellery
The color range for Ruthenium in jewellery includes various shades from silvery white all the way through black, which can be used with plating or even without any coating at all on occasion allowing you to see its natural beauty beneath the sunlight.
- Ruthenium is quite durable, as it maintains its shine and luster for a long time. It is very difficult to create scratches on ruthenium. Thus, making it the perfect jewellery material.
- Ruthenium has similar characteristics to silver, but without the risk of tarnishing or corrosion after a while.
- The downside with this metal is that it can change color under certain conditions. For example, if you have been wearing your ruthenium ring in hot water baths over an extended period, the metal may turn yellowish-brown after some months.
- This may be due to sulfur vapors from polluted air getting into contact with moisture from your skin and sweat. That’s because it reacts together resulting in dark stains on your piece of jewelry.
- If there are chemicals present in the water, this can also affect your ring.
Is Ruthenium-Plated Jewellery Toxic?
Ruthenium is a metal that has very low toxicity and usually does not cause any negative effects when it comes to wearing jewelry. Therefore, ruthenium plating on jewellery is generally harmless.
Ruthenium-plated items are usually hypoallergenic as well. But it’s important to note that they may cause a reaction in those who have nickel allergies or sensitivities. In this case, you should not wear a ruthenium plate. Mainly because the alloy would contain some nickel and your skin will most likely react badly to it.
Does Ruthenium Plating Wear Off in Jewellery?
Ruthenium does not require cleaning and is not reactive. The black ruthenium plating is a more durable plating than the oxidization that is common. The plating will wear away with time, which is considered typical wear and tear rather than a drawback.
Importance of Ruthenium Plating in Jewellery
- Ruthenium plating is used to maintain the metal’s color and prevent it from oxidizing, as well as making it more durable and preserving it from scratches.
- A ruthenium-plated finish has a look that is similar to black nickel plating but with a far more durable finish.
- It has a distinctive dark hue that may be changed from light gray to gray-black.
It’s also the most difficult of all platinum group metals, with an almost indestructible and chemically stable shine.
Trends in fashion tend to go around. Jewelry is becoming increasingly darker. And women are becoming more accustomed to wearing jewellery that complements their wardrobe. While also blending in with their black nail art, lipstick, and hairstyle.
If you are looking to work in the precious metals and jewellery industry, subscribe to our page Mintly.