What This Glossary Covers#
This glossary covers price and trading terms, purity and bullion terms, mining and geology terms, refining and recycling terms, and automotive catalyst terms, each linking to its own page. Term counts per category are listed below.
- Price and trading: 10
- Purity and bullion: 8
- Mining and geology: 3
- Refining and recycling: 11
- Automotive catalyst: 8
Platinum group metal prices are quoted as bid, ask and spot values, all defined below; current figures sit on the platinum group metal prices today page.
Price and Trading Terms#
Platinum group metal trading has its own vocabulary for spreads, forward curves and lending, covering 10 terms from bid-ask spread to allocated metal. Spread width tracks liquidity: on one Kitco snapshot at 00:10 EST on 6 August 2026, the platinum spread was 0.57% of the bid, against 0.05% for gold and 2.95% for palladium. The 10 trading terms are defined below.
| Term | Definition |
|---|---|
| Bid-ask spread | The gap between a dealer's buying price (bid) and selling price (ask); on Kitco's 6 August 2026 snapshot it was 0.05% of the bid for gold, 0.57% for platinum and 2.95% for palladium. |
| Contango | A market in which the forward price sits above the spot price, the normal condition when the cost of carry (interest, storage, insurance) exceeds the convenience yield of holding metal now. |
| Backwardation | A market in which the forward price sits below the spot price; in precious metals it signals physical tightness, because immediate metal commands a premium over future metal. |
| Lease rate | The annualized cost of borrowing physical metal; the most direct observable measure of physical stress in a metal with no exchange stocks data. |
| NYMEX | The New York Mercantile Exchange (CME Group), venue for the PL platinum futures contract (50 troy oz, 99.95% minimum purity) and the PA palladium contract (100 troy oz). |
| Shanghai Gold Exchange (SGE) | Home of China's Pt99.95 physical platinum spot contract, quoted in yuan (CNY) per gram. |
| Platinum Week | The London industry week at which forecasters publish updated platinum balances; at London Platinum Week 2026, Johnson Matthey, SFA (Oxford), BASF and WPIC (data by Metals Focus) each did so, compared side by side in WPIC's review of 29 May 2026. |
| Spot deferred | A spot position rolled forward to a later value date at the prevailing forward rate instead of settling on the T+2 spot value date. |
| Unallocated metal | A general entitlement to a quantity of metal with no specific bars assigned; the holder is an unsecured creditor of the dealer, and it is the basis of loco London clearing. |
| Allocated metal | Specific, identified bars or plates physically segregated and held by the dealer as custodian for the client, off the custodian's balance sheet, with a bar list of serial numbers, weights and assays. |
Purity and Bullion Terms#
PGM purity and bullion terms describe how fineness is stated and how bullion is weighed and delivered, covering 8 terms from fineness to 4E and 6E ounces. Platinum and palladium use millesimal fineness; karat is a gold-only scale. One troy ounce equals exactly 31.1034768 grams; rounding to 31.1 misstates 1 million troy ounces by 3.48 kilograms (about 112 troy oz).
| Term | Definition |
|---|---|
| Fineness | Purity expressed in parts per thousand of the named metal by mass; 999.5 fineness equals 99.95% pure. |
| Good Delivery | The specification a bar, plate or ingot, and its refiner, must meet to be freely acceptable without assay in the wholesale market; LPPM platinum and palladium plates and ingots weigh 1 kg (32.151 troy oz) to 6 kg (192.904 troy oz) at a minimum 99.95%. |
| LPPM | The London Platinum and Palladium Market, founded 1987, which maintains the London/Zurich Good Delivery List of 39 platinum and 33 palladium refiners. |
| Millesimal fineness | The parts-per-thousand purity system as used in hallmarking; Pt950 means 950 parts per thousand platinum, and the UK platinum standards are 850, 900, 950 and 999. |
| Bullion | Investment-grade metal in bars or coins, traded close to the value of its metal content rather than for rarity. |
| Numismatic coins | Coins valued mainly for rarity, condition or collector demand rather than metal content, the opposite of a bullion coin. |
| Troy weight system | The mass system for precious metals: one troy ounce is 480 grains, exactly 31.1034768 g, under the 1959 International Yard and Pound Agreement; 1 kg equals 32.1507466 troy oz. |
| PGM ounces (4E, 6E) | The basket notation producers use for combined PGM output; 4E is platinum, palladium, rhodium and gold, and 6E adds ruthenium and iridium, still excluding osmium. |
Mining and Geology Terms#
PGM mining terms describe where the metal comes from and what it costs to mine, covering 3 terms from reef to all-in sustaining cost. Every cost per ounce depends on its basket: Valterra Platinum reported AISC of US$987 per 3E ounce for 2025 (Annual Results 2025), and a 6E denominator would give a lower figure.
| Term | Definition |
|---|---|
| Reef (mining) | A stratiform, laterally continuous mineralized horizon within a layered igneous complex; the Merensky Reef, UG2 Chromitite and Platreef of the Bushveld Complex are the commercial South African reefs, alongside the J-M Reef in Montana. |
| AISC | All-in sustaining cost, a non-GAAP metric developed under World Gold Council guidance (issued 2013, updated 2018): operating costs plus sustaining capital, sustaining exploration and general costs, per basket ounce. |
| Mine supply | Newly mined PGM sold by miners each year (Johnson Matthey's "primary supply"), which differs from mined production because producers sell from, or build, inventory. |
Refining and Recycling Terms#
PGM refining terms trace the path from mined ore to refined metal, covering 11 terms from prill split to secondary supply. The South African processing chain runs in the six stages below.
- Run-of-mine ore
- Milling and flotation to concentrate
- Smelting to furnace matte
- Converting to converter matte
- Base metals refinery
- Precious metals refinery to refined metal
The 11 terms follow.
| Term | Definition |
|---|---|
| Prill split | The share each element contributes to an ore's or concentrate's PGM basket; Sibanye-Stillwater's South African operations reported a 2025 4E split of platinum 59%, palladium 30%, rhodium 9% and gold 2%. |
| Converter matte | The product of blowing air or oxygen through furnace matte to remove iron and most of the sulfur, raising PGM tenors to 1,500 to 25,000 g/t. |
| PGM concentrate | The flotation product in which PGM-bearing sulfides are upgraded from a few grams per tonne in ore to typically hundreds of grams per tonne. |
| PGM smelter | The electric-furnace stage that melts concentrate into a PGM-bearing furnace matte, separated from a silicate slag. |
| Base metal refinery | The stage that leaches nickel, copper and cobalt out of converter matte, leaving a PGM-rich residue for the precious metals refinery. |
| Aqua regia | A mixture of hydrochloric and nitric acids that dissolves platinum and palladium but leaves rhodium, iridium, ruthenium and osmium largely insoluble; industrial primary refining uses chlorine in hot hydrochloric acid instead. |
| Fire assay | The classical technique that collects precious metals into a lead or nickel-sulfide button; nickel-sulfide collection is the reference method for the full PGE suite, including ruthenium, iridium and osmium. |
| Refining charge | The fee for refining payable metal to final purity, quoted per unit of payable metal (per ounce, pound or kilogram). |
| Recovery rate | The percentage of contained metal in the feed that reports to saleable product at a stage; concentrator, smelter and refinery recoveries multiply into the overall figure. |
| Decanning | Removing a spent catalytic converter's steel shell to free the ceramic or metallic substrate for PGM recovery; the steel is sold as its own scrap stream. |
| Secondary supply | Metal recovered by open-loop recycling and returned to the market; Johnson Matthey excludes closed-loop recycling, which returns metal to the same user. |
Automotive Catalyst Terms#
PGM autocatalyst terms describe how platinum, palladium and rhodium clean vehicle exhaust, covering 8 terms from PGM loading to catalyst monolith. Ruthenium, iridium and osmium are essentially absent from autocatalysts, so a converter's recoverable PGM value rests on the three metals alone.
| Term | Definition |
|---|---|
| PGM loading | The PGM content of a catalyst, stated in grams per catalyst or per vehicle. |
| Thrifting | Reducing the mass of PGM required per unit of catalytic function without substituting a different metal; it is asymptotic, each halving harder than the last. |
| Washcoat | The alumina and ceria coating that carries dispersed PGM particles on a catalyst's ceramic or metallic substrate. |
| Cordierite | The ceramic (2MgO·2Al2O3·5SiO2) used as the substrate of most light-duty gasoline three-way catalysts and most diesel oxidation catalysts; the metallic alternative is FeCrAl foil. |
| Three-way catalyst | The main gasoline emissions-control technology, using platinum, palladium and rhodium to oxidize CO and hydrocarbons while reducing NOx to nitrogen; rhodium is the irreplaceable NOx component. |
| Diesel oxidation catalyst | A platinum- and palladium-based catalyst that oxidizes CO, hydrocarbons and the soluble organic fraction of diesel particulate. |
| Gasoline particulate filter | A wall-flow filter trapping soot from gasoline direct-injection engines; Euro 6c's particle-number limit of 6×10^11 per km made it the practical compliance route, though no EU regulation names it. |
| Catalyst monolith | The honeycomb substrate, cordierite ceramic or FeCrAl metal foil, onto which a catalyst's washcoat is applied. |
General PGM Classification and Further Reading#
Two terms describe the PGMs' place among metals generally rather than a single market process. Three questions on distinctions from the tables follow them.
Noble Metals and Precious Metals#
Noble metals and precious metals overlap but are not identical categories; the two terms are defined together below. Noble describes chemical behavior; precious describes a market category.
| Term | Definition |
|---|---|
| Noble metals | Metals that resist corrosion and oxidation; the ADA/ANSI dental-alloy classification counts gold, platinum, palladium, iridium, osmium, rhodium and ruthenium as noble metals. |
| Precious metals | The high-value traded metals: gold, silver, platinum and palladium carry the four LBMA precious metal benchmarks, administered by ICE Benchmark Administration (for platinum and palladium since 1 July 2026), while rhodium, iridium, ruthenium and osmium trade on dealer quotes. |
Glossary FAQ#
What does PGM stand for?#
PGM stands for platinum group metals: platinum, palladium, rhodium, iridium, ruthenium and osmium, considered as traded commodities. Geologists call the same six elements PGE, platinum group elements.
What is the difference between allocated and unallocated metal?#
Allocated metal is specific, identified bars held as custodian for the client; unallocated metal is a general entitlement with no bars assigned, making the holder an unsecured creditor of the dealer. Allocated holdings carry a storage charge; unallocated holdings are cheaper and more liquid.
What is the difference between 4E and 6E ounces?#
4E ounces are platinum, palladium, rhodium and gold; 6E ounces are platinum, palladium, rhodium, ruthenium, iridium and gold, excluding osmium from both. Sylvania Platinum reported 81,002 oz 4E and 104,233 oz 6E for the year to 30 June 2025 from the same material. A 6PGE assay figure includes osmium and excludes gold.