Rhodium (Rh, element 45) and platinum (Pt, element 78) are both platinum group metals, but rhodium trades at several times platinum's price while platinum remains the far larger, more liquid market. Among the platinum group metals compared on this site, this pairing is the most price-lopsided. The two metals also differ sharply in density, melting point, hardness and magnetic behavior, and they are combined, not just compared, in a small number of high-temperature industrial alloys.
Rhodium vs Platinum at a Glance#
Rhodium costs roughly 4.6 to 4.9 times as much as platinum per troy ounce, based on dated dealer quotes from early August 2026 (Kitco, Trading Economics). The table below sets the two metals' identity, price and core physical properties side by side; every figure carries its own date and source, and the two price series are kept separate rather than blended into one number.
| Metric | Rhodium (Rh) | Platinum (Pt) |
|---|---|---|
| Price, Kitco spot bid, 5 Aug 2026 | $8,200.00/oz | $1,749.00/oz |
| Price, Trading Economics, 6 Aug 2026 | $8,525/oz | $1,763.30-1,768.00/oz |
| Atomic number | 45 | 78 |
| CAS number | 7440-16-6 | 7440-06-4 |
| Density, 20 degrees C | 12.423 g/cm3 | 21.452 g/cm3 |
| Melting point | 1,964 degrees C (2,237 K) | 1,768.3 degrees C (2,041.4 K) |
| Mohs hardness | 6.0 | 3.5 |
| Magnetic ordering | Paramagnetic | Paramagnetic |
Rhodium Price vs Platinum Price#
Rhodium traded at $8,200.00-8,525 per troy ounce against platinum's $1,749.00-1,768.00 on 5-6 August 2026, on Kitco spot and Trading Economics quotes respectively. Dividing the two series against each other puts rhodium at roughly 4.6 to 4.9 times platinum's price on that dated pair, a ratio that moves with both metals' quotes and is not a fixed multiple.
Current levels for both metals are tracked separately on this site's rhodium price today and platinum price today pages, which update through the trading day; the figures above are dated historical points, not live quotes, and the two vendor series are never averaged into a single blended price.
Why Rhodium Trades So Far Above Platinum#
Rhodium costs more than platinum because it has no substitute as the NOx-reduction catalyst in three-way autocatalysts and its entire annual market is roughly 1 million ounces, against platinum's much larger, exchange-traded market. Rhodium has no metals exchange, no futures contract and no exchange-traded fund of its own, so a comparatively small shift in autocatalyst buying or South African mine supply moves its price far more than the same dollar shift would move platinum, which trades on NYMEX futures, sits in multiple bullion ETFs and is assessed twice daily in the LBMA benchmark auction.
Rhodium vs Platinum: Physical and Chemical Properties#
Rhodium and platinum differ most in density and melting point: platinum is the denser, heavier-feeling metal and rhodium melts at a higher temperature. Full elemental profiles for rhodium (Rh), element 45 and platinum (Pt), element 78 cover each metal's chemistry beyond this side-by-side comparison.
Density: Rhodium vs Platinum#
Platinum is about 72.7% denser than rhodium, at 21.452 g/cm3 against rhodium's 12.423 g/cm3 at 20 degrees C. Rhodium plating itself is only a few microns thick, so a rhodium-plated item's weight is governed by its base metal, not by that thin rhodium layer.
| Property | Rhodium | Platinum |
|---|---|---|
| Density, 20 degrees C | 12.423 g/cm3 | 21.452 g/cm3 |
| Melting point | 1,964 degrees C / 2,237 K / 3,567 degrees F | 1,768.3 degrees C / 2,041.4 K / 3,214.9 degrees F |
| Vickers hardness | 1,100-8,000 MPa (upper end electrodeposited) | 400-550 MPa |
| Brinell hardness | 980-1,350 MPa | 300-500 MPa |
| Mohs hardness | 6.0 | 3.5 |
Melting Point and Hardness#
Rhodium melts at 1,964 degrees C (2,237 K), about 196 degrees higher than platinum's 1,768.3 degrees C (2,041.4 K), and is also the harder of the two metals, Mohs 6.0 against platinum's 3.5. On Vickers hardness rhodium spans 1,100 to 8,000 MPa and platinum spans only 400 to 550 MPa, but the 8,000 MPa figure describes electrodeposited rhodium, the thin, hard, brittle layer built up by electroplating, not wrought rhodium metal; never quote that upper figure as rhodium's hardness without the electroplated qualifier. On Brinell hardness rhodium runs 980 to 1,350 MPa against platinum's 300 to 500 MPa. Rhodium's extra hardness is why a rhodium-plated surface resists scratching better than bare platinum, while platinum's own softness is what lets it be cast and set with stones without cracking.
Is Rhodium or Platinum More Magnetic?#
Neither rhodium nor platinum is attracted to a magnet in the everyday sense: both are paramagnetic, with platinum's molar susceptibility (+201.9 x10-6 cm3/mol) nearly twice rhodium's (+111.0 x10-6 cm3/mol). Paramagnetism is a weak, non-permanent response to a magnetic field, unlike the strong, permanent pull of a ferromagnetic metal such as iron, so a standard jewelry or pocket magnet will not pick up either metal and cannot tell them apart.
Rhodium and Platinum Together: Alloys and Plating#
Rhodium and platinum are combined, not just compared, in platinum-rhodium thermocouple wire and platinum-rhodium catalyst gauze, because both metals resist oxidation as bare metal above 1,200 degrees C. Rhodium and platinum are the only two platinum group metals that can be used as bare, uncoated metal in flowing air at that temperature without rapidly burning away as a volatile oxide; a 1963 oxidation-rate study on the platinum group metals (Krier and Jaffee, Journal of the Less-Common Metals) found iridium loses metal roughly 320 times faster than platinum at 1,400 degrees C. That shared stability is why platinum-rhodium wire is the standard material for type R and type S thermocouples and for the high-temperature glass-fiber bushings used to draw molten glass.
Rhodium vs Platinum as Catalysts#
Platinum-rhodium gauze catalyzes industrial ammonia oxidation in nitric acid production, and the same two metals, plus palladium, make up the three-way catalyst in vehicle exhaust systems. In the nitric acid process, ammonia and air pass through a woven platinum-rhodium gauze pack that converts ammonia to nitric oxide, a use that depends on the same oxidation resistance described above. In a vehicle's three-way catalytic converter, rhodium performs the reduction half of the reaction, converting nitrogen oxides back to nitrogen, while platinum and palladium oxidize carbon monoxide and unburned hydrocarbons; rhodium has no commercial substitute for that role, which is why its price is so sensitive to shifts in automaker demand.
Which Is Rarer: Rhodium or Platinum?#
Rhodium is the rarer metal in production terms: Johnson Matthey's PGM Market Report (May 2026) puts world primary rhodium supply at about 21.8 tonnes (701,000 oz) for 2025, against platinum's much larger, actively traded market. That production is also far more geographically concentrated than platinum's:
- South Africa supplies about 82% of the world's primary rhodium, per IPA/SFA (Oxford) rhodium supply data, the tightest geographic concentration of any platinum group metal, so a single country's mine disruptions can move the global rhodium price.
- Rhodium's primary supply is roughly 3.1 times iridium's, for context against the other minor PGMs, though rhodium remains a small fraction of platinum's much larger annual mine output.
- Rhodium has no metals exchange, no futures market and no dedicated ETF, which is a rarity of market structure on top of its rarity of physical supply.
Deeper supply and demand detail for the metal sits on this site's rhodium market page, which tracks the same South African production base against year-on-year demand from the automotive sector.
Rhodium and Platinum Prices, Scrap and Investment#
The rest of this page covers where to track both metals' live prices, how their scrap is valued, and the questions readers ask most often about the pair.
Rhodium and Platinum Price Pages#
Live prices for both metals, plus units and history, have dedicated pages on this site:
- Rhodium price history: annual prices, highs and lows for rhodium going back across market cycles.
- Platinum price history: the same annual view for platinum, for direct year-by-year comparison.
- Rhodium price chart: a live and historical charting view of the rhodium quotes shown above.
Full annual detail sits on the rhodium price history and platinum price history pages, and the rhodium price chart plots the series shown in the table above against its longer-run range.
Selling Rhodium and Platinum Scrap#
Rhodium and platinum scrap are valued on their metal content, not gross weight, and both are recovered mainly from spent autocatalysts. A buyer assays the actual rhodium or platinum content of a converter or plated item and pays against that contained-metal value at the day's price, not against the item's total weight, which is why two similarly sized lots can be worth very different amounts. Readers selling material can check the scrap platinum price and rhodium scrap pages for how each metal's scrap is assayed and priced, and readers considering the metals as a holding rather than a sale can see the risk and product profile on the rhodium investment page.
Rhodium and Platinum FAQ#
Is rhodium more expensive than platinum? Yes: rhodium traded at $8,200-8,525/oz against platinum's $1,749-1,768/oz on 5-6 August 2026 (Kitco, Trading Economics), roughly 4.6 to 4.9 times platinum's price on those dated quotes.
Does a magnet stick to rhodium or platinum? No: both rhodium and platinum are paramagnetic, not ferromagnetic, so neither is attracted to a magnet in normal use.
What country produces the most rhodium? South Africa supplies about 82% of the world's primary rhodium, the tightest geographic concentration of any platinum group metal.
What is a platinum-rhodium alloy used for? Platinum-rhodium alloy is used mainly as thermocouple wire (type R and type S) and as catalyst gauze for nitric acid production, both applications relying on its high-temperature oxidation resistance.
What are rhodium's and platinum's symbol, atomic number and CAS number? Rhodium has the symbol Rh, atomic number 45 and CAS number 7440-16-6; platinum has the symbol Pt, atomic number 78 and CAS number 7440-06-4.