I first laid eyes on rhodium jewelry when I went to buy gold bangles for myself. What I came home with, was a stunning pair of bangles that were really shiny. The shine came from the rhodium polish on them. I loved the look rhodium gave to those otherwise simple bangles and wanted to know more about it instantly. I did some fact finding on the topic myself, and hereby bring everything I have learnt about it.
Rhodium in itself is a highly valuable metal. It costs about three times more than gold. However, it is not possible to cast a piece of jewelry out of pure rhodium owing to its properties. This is the reason why most pieces of Rhodium jewelry contain rhodium polish. Rhodium being extremely shiny, it adds to the sheen of the jewelry item in addition to increasing the value.
Lets commence with understanding what rhodium really is as a metal. and what are its properties which make it useful as a metal avidly used in jewelry making.
What is Rhodium and how is it useful in making jewelry?
Represented by the symbol Rh and an atomic number of 45 on the periodic table, Rhodium is basically a white and lustrous metal which is found and mined from the proximity of platinum ore.
However the real reason why this metal has been extensively used in crafting jewelry is its unique physical and chemical properties, as listed below.
1. SHINY APPEARANCE : Belonging to the platinum family, it is gleaming and striking white in color.
2. CHEMICALLY UNREACTIVE : We all know very well that corrosion can make the most intricate and ornate pieces of jewelry look pitiable. This is where rhodium being an inert and noble metal, does not react with chemicals in the vicinity, and hence jewelry crafted out of it does not corrode. This also makes it a perfect metal for coating and plating jewelry, hence rendering corrosion resistance to the jewelry pieces.
3. SCARCITY : Being found in one part per 200 million in the earth’s crust, Rhodium is a very rare metal, which makes it rather valuable and hence a perfect metal for crafting valuable jewelry pieces out of.
4. In addition, Rhodium works very well with other base metals used in making jewelry such as gold and silver and fills cracks and gaps in these with perfection. Thus, making scratched pieces shiny again.
Why is pure Rhodium jewelry not available?
Like we mentioned, rhodium is mainly used in electroplating of gold as well as silver jewelry, and yet jewelry is not made out of solid rhodium. The main reasons why rhodium is not used in making jewelry, in its purest form are as follows :
- A HIGH MELTING POINT : Rhodium as a raw form metal, has a very high melting point (1964 degree Celsius), which is really a very high temperature to reach and hence melt the metal to craft it into jewelry is expensive and dangerous.
- RARE AND SCARCE DEPOSITS : Rhodium is one of the rarest metals available on earth and this is what makes it really hard to find and hence use for making jewelry in its rarest form. The most concentrated deposits of rhodium are just about a hundred few thousand ounces, and this signals how scare it really is in its availability.
How long does Rhodium plating last?
While Rhodium plating can last anywhere between 3 months- 3 years. The life of Rhodium plating depends a lot on your handling of the piece. The major factors are friction the piece is subject to and it’s exposure to chemicals.
- Friction A piece that is handled roughly and comes in frequent contact with other objects will only be able to retain the plating for 3-4 months. At the same time, a piece that is not worn round the clock and is handled carefully can last upto 2-3 years.
- Exposure to Chemicals The life of plating also depends on the exposure to harmful chemicals as well. So if you apply perfume on your neck and you are wearing a Rhodium plated necklace, it’s life may be impacted. If you are wearing Rhodium plated ring and you do the dishes without removing your ring or wearing protective gloves, the plating will come off sooner. This will be a result of exposure to harmful chemicals in the dish washing soap. Harsh chemicals in your bathing or hand washing soap may lead to similar consequences.
Comparison Below is a comparison between the Rhodium plating of 2 bangles I bought at the same time. I started wearing fitbit on one hand so I removed 1 bangle. After 6 months, I took it out to wear and the difference was unbelievable. Now i have been wearing the pieces for about 6 months and this is how they both look now.
How can you tell if Jewelry is Rhodium plated?
Platinum or coated silver jewelry can appear similar to rhodium polished jewelry. If you want to be sure about your jewelry, there are certain ways that can help even a novice.
For older pieces of jewelry:
As rhodium plating is not permanent, it wears off with regular use. This makes it easy to find cues in your older piece of jewelry.
Inspecting the areas that come in frequent contact with other objects you can tell if your piece of jewelry is rhodium plated. Like the side bend of your ring, the edges of your bangles. You will be able to see the color of the base metal (yellow, if the base metal is gold) from these parts if you observe your piece under good lighting.
For brand new jewelry items:
- Your jeweler is the best person for helping you with complete details on your jewelry item. You can get complete details of which metal is used as the base and which metal is plated on top. However, it might not always be possible to get help from a jeweler (e.g. if a piece of jewelry is gifted to you).
- Rhodium polish is primarily done on the outer (visible) areas of a piece of jewelry, and is done as the top coat (or plating). Inspecting the parts that are not visible from the outside will help you determine if the piece is polished or not. E.g., inspect the inside of the ring band, the back of your earring or pendant, the inner arch of your bangle. The top layer will have a chrome finish and a subtle silvery-shine, while the base will be in a tone of yellow (color will vary based on the carats of your piece of jewelry). If the color is same throughout and you do not notice any yellow tones, your piece might be platinum, which is generally more expensive.
- Also, hallmarks can give some details on your piece. Check the inner arcs or hidden parts of your jewelry for hallmark signs. If it is marked as gold, e.g 18 K or 22 K and the color is on the silver side, the probability of it being rhodium polish is high.
- You can try scratching a less visible area as thickness of rhodium plating is thin and comes off easily when scratched with something harder. This will allow you to see the underlying layer. If you notice a difference in tone or you see a completely different color underneath, you will know that your jewelry is rhodium plated.
Which is better Platinum plated or Rhodium plated?
If we compare different metals used in coating, hardness and melting point of the metal play an important role. This is because, if the metal used for plating is harder, the chances of it getting scratched I daily wear are lesser than a metal which is softer. Additionally, for use in jewelry, the shinier the metal. the shinier the piece of jewelry will be. So let’s compare these metals on these points.
Hardness of the metal
The level of softness on Mohs scale can help understand the concept better. A metal rated higher on Mohs scale is harder than any metal rated below it.
Platinum has a rating of 4 on Mohs scale. The hardness of Rhodium on the scale is 6. Thus, making rhodium harder and making Rhodium plated jewelry more robust.
Shine of the metal
There is no other metal that can outshine Rhodium. So if we compare the shine of a rhodium plated piece of jewelry with a platinum plated piece, the Rhodium plated piece will be shinier.
Melting Point
Platinum has a slightly lower melting point than Rhodium. Both are difficult to manage in molten state. The melting point of Platinum is 1768 degree Celsius and that of Rhodium is 1963 degree Celsius.
Corrosion Resistance
While both Platinum and Rhodium are resistant to corrosion, Rhodium is more resistant.
Brittle
Rhodium is brittle while platinum is not. Rhodium primarily becomes brittle when the thickness exceeds 1.0 microns. Platinum is highly malleable and is not brittle.
Intermediate layer
When coating with Rhodium, an intermediate layer of silver or nickel is used. This is imperative due to Rhodium being brittle. Platinum is usually used in pure form.
Life
As platinum can be coated in thick layers ranging from 0.125 microns to 25 microns, the life of platinum platinum plating is higher. The thickness of Rhodium plating is normally between 0.5 microns to 2.5 microns. Thus, it forms a thin layer which gets removed faster as a result of friction when compared to platinum plating.
| Feature | Platinum | Rhodium |
|---|---|---|
| Hardness | Softer than Rhodium (4 on Mohs scale) | Harder ( 6 on Mohs scale) |
| Shine | Less shinier than Rhodium | Rhodium is shinier |
| Melting Point | 1768 degree C | 1963 degree C (Higher) |
| Corrosion Resistance | Resistant but less than Rhodium | Higher Resistance |
| Brittle | Less brittle and more malleable | Brittle and less malleable |
| Intermediate layer | No intermediate layer required | An intermediate silver or nickel layer is required |
| Life | Longer life | Lesser life as metal is brittle and has thin layer of coating |
THE VALUE PROPOSITION
Is Rhodium a precious metal?
Yes, Rhodium is a precious metal. In fact, Rhodium is the most valuable and expensive metal on earth. You may have to pay around $450 for a gram of Rhodium while you only pay about $50-$60 for a gram of Gold. Platinum only costs about $30 per gram. This makes Rhodium about 6 times more expensive than gold and even more expensive than Platinum.
Why is Rhodium so expensive?
Limited availability, shine and being corrosion resistant are some of the factors that make Rhodium so expensive. Let us look at the features in detail.
- Availability: It is scarce in terms of natural availability. It is primarily found during nickel and platinum mining or during mining of other platinum group metals. Limited availability makes the metal expensive.
- Difficulty Extraction: Rhodium is difficult to extract and can only be cultivated in small quantities. It is mined with other minerals in it’s natural form. Rhodium and platinum are extracted together. Then the two metals are separated.
- Shine: Rhodium is highly reflective which makes it extremely shiny. It makes a piece of jewelry shinier. This makes it suitable for all types of jewelry be it necklaces, bangles, rings, earrings, pendants or anything else you can possibly think of. It particularly brings out the shine of diamonds and goes well with diamond jewelry as well.
- Hardness: The metal is really hard. As discussed above, it rates a 6 on Mohs scale. Thus it adds to the strength of the jewelry item it is plated on. Being hard, it is also difficult to scratch. Therefore it prevents the underlying metal against scratches.
- Corrosion Resistant: Rhodium is resistant to corrosion. It is used to plate metals that are more susceptible to corrosion. E.g. Silver pieces are Rhodium plated as silver may have traces of copper or nickel and may tarnish over time.
- Non-toxic: Rhodium is hypoallergenic in addition to being anti-tarnish. This makes it suitable for use in kids jewelry on in jewelry made for people with sensitive skin. It would not react with the skin to cause rashes or would not turn the skin green.
- Use in automobile industry: Major share of Rhodium (about 80%) is used by the automobile industry and not jewelry. Due to the high demand in the industry, the metal is expensive.
- Demand: Owing to the above features, there is a huge demand of the metal. Huge demand and limited availability make the metal more expensive.
Is Rhodium plated jewelry valuable?
While Rhodium in itself is highly valuable, Rhodium plated jewelry may or may not be valuable. One can find invaluable jewelry items made from nickel but plated with Rhodium for $15. Having said that, prices of rhodium plated ring could be as high as $4000.
- Cost of Base metal: The actual cost of a Rhodium plated jewelry would depend on the constituting base metal. A ring with base metal as nickel would be far cheaper than a ring with base metal as 22 carat gold.
- Quality of Rhodium: Low quality and thin layer of Rhodium is plated on inexpensive items. Good quality plating with considerably thicker layer of coating will cost more.
- Size of the metal: A bigger piece of Rhodium plated jewelry with more surface area will cost more. The increased cost would be owing to the cost of Rhodium required to plate the surface area.
Apart from the cost of jewelry, Rhodium jewelry also has an additional cost of upkeep. A piece may require replating every 6 months to 2 years. The cost could be about $40-$100 to replate a piece of ring. So you must consider the same while investing in a piece of Rhodium plated jewelry. Having said that, some premium jewelers also provide free re-plating services. So you must check with your jeweler when you invest in such a piece.
Rhodium being a rare metal will always hold value. However, it is not possible to cast jewelry items out of pure Rhodium. Therefore, Rhodium plated items are available in the market. Additionally, it adds to the strength and longevity of underlying metals in addition to making them shinier and pleasing to the eyes. Thus, making it a popular metal. You may invest in one if you like the shine it brings to a piece of jewelry. I hope the above information was helpful.
Until next time! 🙂
