What is Rhodium a.k.a. 'The King of Platinum'

What is Rhodium? What is all the fuss about Rhodium Plating? In this article we will explore the secret identity of Rhodium and why is it so important to us.

Rhodium is one of the rarest metals on earth, which also makes it one of the most expensive. It is an extremely durable element that has a gorgeous pure silver-white color that is highly reflective and resistant to corrosion.

In fact it is considered the rarest and most valuable precious metal in the world

“Well above Gold or Silver

Gold and precious metal mining in California - Currier & Ives c.1871

The Origin of the name “Rhodium”

Rhodium is a beautiful word that comes from the Ancient Greek word "rhodon," which means rose. This romantic named is named after the rose-red color of its salts when it was initially discovered.

Though not as interesting, here are some facts on Rhodium for the geeks

  • Atomic number (number of protons in the nucleus): 45
  • Atomic symbol (on the periodic table of the elements): Rh
  • Atomic weight (average mass of the atom): 102.90550
  • Density: 12.41 grams per cubic centimeter
  • Phase at room temperature: Solid
  • Melting point: 3,567 degrees F (1,964 degrees C)
  • Boiling point: 6,683 degrees F (3,695 degrees C)

Rhodium electrons and neutrons, Rh a noble metal that shines

We are The King of Platinum

Rhodium is one of the of the six platinum group metals:

  1. Platinum
  2. Palladium
  3. Osmium
  4. Iridium
  5. Ruthenium
  6. Rhodium

Like a king, rhodium and the family of the platinum are noble metal, we does not react to oxygen easily which gives us the resistant to corrosion and oxidation.

Some other common characteristics of our platinum family metals include high melting points, general non-toxicity, and high resistance to wear, oxidation and corrosion.

This is the reasons Jewelry industry Loves Us

The family of the nobles, the platinum family, the precious metal family

Of all platinum group metals, Rhodium is the rarest of all, only occurring up to one part per 200 million in the Earth's crust. That is 1 part per 200,000,000 in the Earth's crust (Eight 0's). Rhodium has lower density and a higher melting point than the more common platinum.

To showcase how noble is this exceptional metal, Rhodium is unaffected by air and water up to 1,112 degrees Fahrenheit (600 degrees Celsius), which makes it to be the precious metal of choice to many renounced jewelry manufactures.

History on how is Rhodium being “Discovered”?

Long long ago in a far away land, around 200 years ago in year 1803, Rhodium was discovered by an English chemist named William Hyde Wollaston.

On a thought to be a boring day of the chemist, Wollaston was working with a piece of rare platinum ore he had obtained from South America. After a series of complex chemical reactions, Wollaston was able to remove the platinum and palladium from the sample of platinum ore. What was left was dark red powder, which at time is unknown.

His colleagues, a French chemist called Hippolyte-Victor Collet-Descotils alerted Wollaston to the possibility of a new element existing in platinum ore, and they believed that the red color of some platinum salts was due to the presence of an unidentified metal. It was later turned out to be sodium rhodium chloride.

Rhodium powder

Looking at the beautiful red emitted by this strange power, they decided to name it Rhodium, a name inspired by the enchanting colors of the rose.

Wollaston have successfully extracted rhodium from a piece of platinum ore that he had obtained from South America.

Rhodium are more usually found in tiny traces with deposits of platinum and is obtained from series of mining and refining of platinum ore. Rarely will you find a piece of Rhodium lying around.

Origin of Rhodium

What is Rhodium used for?

Earth’s Hero

One of the amazing use for rhodium is in catalytic converters designed to clean vehicle emissions. Rhodium often together with other metals from the platinum family such as palladium and/or platinum accomplishes this by reducing nitrogen oxide in exhaust gas. To place it simply, without rhodium catalysts, the air in our cities will not be breathable due to vehicle exhausts.

High tech

Rhodium with its unique properties is often alloyed with platinum and iridium to make an oxidation-resistant metal that can stand against high temperatures. These alloys are metal of choice for the use of high tech electronics placed in aircraft.

Fine Jewelry Industry, Shine Like The King

Special property of rhodium is that is absolutely brilliant and resistant to tarnishing, silver and gold can only be kept its brilliance when it is coated with the royal coat of Rhodium that is used as a finish for most Precious Jewelry.

Rhodium being one of the rarest of the precious metal, it is the precious metal of choice for most of the major brands in the industry to be used to perform metal plating for the Fine Jewelry Collections. Its brilliance and the durability is unmatched in the family of platinum metals.

Price of Rhodium that makes Gold Cheap!

What can actually be more valuable than Gold? Well, platinum are actually a class of precious metal that can be rarer than gold and thus the price. In fact Rhodium is one of the rarest of all and can be much more expensive than gold.

Due to its rarity in combined with the small market size and the concentrated supply, South Africa alone produces roughly 80 percent of the world's rhodium which leads to the prices to become very volatile, according to Mining.com.

To illustrate its volatility, an ounce of Rhodium briefly reached $10,025 just before the 2008 financial crisis hit, but then plunged a whopping 90 percent before the end of the year. In 2018, the price of rhodium is more than Qua-triple to approx. $2,390 an ounce compared to 12-year-lows in mid-2016.

Gold on the other hand is currently price at $1,194 an ounces while Rhodium is at $2,390 an ounces as of time of writing on 05 September 2018, reported by Businessinsider.com.

Today an ounce of Rhodium is worth twice more than Gold.

Gold vs Rhodium vs Platinum comparison

Fun Fact

  • Rhodium is resistant to most acids.
  • Rhodium metal is rarely used by itself and almost always as an alloy.
  • An alloy of rhodium-platinum is used in heart pacemakers.
  • South African Platinum Group Metals (PGM) producers extract a mix of metals comprising approx. 60 percent platinum, 30 percent palladium and as low as only 10 percent rhodium, research by Mining.com.

More about Rhodium can be found in the article Here.

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