Editing Precious metal (section)

==Bullion==
{{Main|Bullion}}

[[File:1000oz.silver.bullion.bar.top.jpg|thumb|right|1,000&nbsp;oz silver bar]]
A metal is deemed to be ''precious'' if it is rare. The discovery of new sources of ore or improvements in mining or refining processes may cause the value of a precious metal to diminish. The status of a "precious" metal can also be determined by high [[demand]] or [[market value]]. Precious metals in bulk form are known as ''bullion'' and are traded on [[commodity market]]s.  Bullion metals may be cast into [[ingot]]s or minted into [[coin]]s.  The defining attribute of bullion is that it is valued by its mass and purity rather than by a [[face value]] as [[money]].

===Purity and mass===
[[File:Johnson Matthey 500 grammes silver bullion.jpg|thumb|left|500&nbsp;g silver bullion bar produced by [[Johnson Matthey]]]]

The level of purity varies from issue to issue. "Three nines" (99.9%) purity is common. The purest mass-produced bullion coins are in the [[Canadian Gold Maple Leaf]] series, which go up to 99.999% purity. A 100% pure bullion is nearly impossible: as the percentage of impurities diminishes, it becomes progressively more difficult to purify the metal further. Historically, coins had a certain amount of weight of [[alloy]], with the purity a local standard. The [[Krugerrand]] is the first modern example of measuring in "pure gold": it should contain at least {{frac|12|11}} [[Troy ounce|ounces]] of at least {{frac|11|12}} pure gold. Other bullion coins (for example the [[Sovereign (British coin)|British Sovereign]]) show neither the purity nor the fine-gold weight on the coin but are recognized and consistent in their composition.{{Citation needed|date=January 2010}} Many coins historically showed a [[denomination (currency)|denomination]] in currency (example: American [[double eagle]]: $20).

===Coinage===
[[File:Philharmoniker 99 front.jpg|thumb|1&nbsp;oz [[Vienna Philharmonic (coin)|Vienna Philharmonic gold coin]]]]

Many nations mint [[bullion coin]]s.  Although nominally issued as [[legal tender]], these coins' face value as currency is far below their value as bullion. For instance, Canada mints a [[gold coin|gold bullion coin]] (the [[Canadian Gold Maple Leaf|Gold Maple Leaf]]) at a face value of $50 containing one troy ounce (31.1035 g) of gold, as of January 2022. The USD to CAD exchange rate averaged 1.129 in July 2009 according to [http://www.oanda.com/currency/historical-rates OANDA Historical Exchange Rates]. Although the exact moment that the $1,075 figure{{clarify|date=November 2024}} was determined is unknown, it may be considered a reasonable value for the time. Bullion coins' minting by national governments gives them some [[numismatism|numismatic]] value in addition to their bullion value, as well as certifying their purity.

[[File:2005 AEPlat Proof Obv.png|thumb|left|200px|[[American Platinum Eagle]] bullion coin]]

One of the largest bullion coins in the world was the 10,000-dollar [[Australian Gold Nugget]] coin minted in Australia, which consists of a full kilogram of 99.9% pure gold. In 2012, the Perth Mint produced a 1-tonne coin of 99.99% pure gold with a face value of [[Australian dollar|$]]1 million AUD, making it the largest minted coin in the world with a gold value of around [[Australian dollar|$]]50 million AUD.<ref>{{Cite web |title=Australian Kangaroo One Tonne Gold Coin |url=https://www.perthmint.com/visit/attractions/one-tonne-gold-coin/ |access-date=28 March 2023 |website=www.perthmint.com.au}}</ref> China has produced coins in very limited quantities (less than 20 pieces minted) that exceed {{convert|8|kg|ozt}} of gold.{{Citation needed|date=January 2010}} Austria has minted a coin containing 31&nbsp;kg of gold (the [[Euro gold and silver commemorative coins (Austria)#Vienna Philharmonic Coin|Vienna Philharmonic Coin]] minted in 2004 with a face value of 100,000 euro). As a stunt to publicise the 99.999% pure one-ounce Canadian Gold Maple Leaf series, in 2007 the [[Royal Canadian Mint]] made a 100&nbsp;kg 99.999% gold coin, with a face value of [[Canadian dollar|$]]1 million, and now manufactures them to order, but at a substantial premium over the market value of the gold.<ref>{{Cite web |title=the Greatest coined gold in the world |url=http://www.e-allmoney.com/article/big_gold_coin.html |url-status=dead |archive-url=https://web.archive.org/web/20160304001451/http://www.e-allmoney.com/article/big_gold_coin.html |archive-date=4 March 2016 |access-date=23 July 2015 |website=e-allmoney.com}}</ref><ref>{{Cite web |last=UKBullion |year=2014 |title=100kg Fine Gold Coin |url=https://www.ukbullion.com/100kg-fine-gold-coin-royal-canadian-mint |access-date=2014-03-18 |archive-date=2014-02-27 |archive-url=https://web.archive.org/web/20140227181052/https://www.ukbullion.com/100kg-fine-gold-coin-royal-canadian-mint |url-status=live }}</ref>

The [[Reserve Bank of Zimbabwe]] mints the gold [[Mosi-oa-Tunya (coin)]] which is recognized as [[legal tender]] at the market value for its gold content.<ref>{{Cite web
 |title       = Zimbabwe debuts gold coins as legal tender to curb inflation but it may be out of reach for the average citizen
 |publisher   = [[ABC News (Australia)]]
 |url         = https://www.abc.net.au/news/2022-07-25/zimbabwe-gold-coins-to-curb-inflation/101268850
 |date        = 25 Jul 2022
 |access-date  = 9 November 2023
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20231101095936/https://www.abc.net.au/news/2022-07-25/zimbabwe-gold-coins-to-curb-inflation/101268850
 |archive-date = 1 November 2023
 |df          = dmy-all
}}</ref>

===Economic use===
[[Gold as an investment|Gold]] and [[silver as an investment|silver]], and sometimes other precious metals, are often seen as defensive assets against both [[inflation]] and economic downturn. [[Silver coin]]s have become popular with collectors due to their relative affordability, and, unlike most gold and platinum issues which are valued based upon the markets, silver issues are more often valued as collectibles, at far higher than their bullion value.<ref>{{Cite journal |last=Aharon DY, and Qadan M. |date=2018-10-04 |title=What drives the demand for information in the commodity market? |journal=Resources Policy |volume=59 |pages=532–543 |language=en |doi=10.1016/j.resourpol.2018.09.013 |bibcode=2018RePol..59..532A |s2cid=158268743 |issn=0301-4207}}</ref>

===Industrial use===
[[Platinum]] and [[palladium]] are key catalysts in [[hydrogenation]] reactions and emission-reducing catalytic converters,<ref>{{cite journal |last1=Chidunchi |first1=Irina |last2=Kulikov |first2=Maxim |year=2024 |title=Extraction of platinum group metals from catalytic converters |journal=Heliyon |volume=10 |issue=3 |page=e25283 |doi=10.1016/j.heliyon.2024.e25283|doi-access=free |pmid=38327460 |pmc=10847661 |bibcode=2024Heliy..1025283C }}</ref> while gold is used in oxidation reactions and nanotechnology due to its stability.<ref>{{cite book |last1=Quanquan |first1=Shi |last2=Youhai |first2=Chio |year=2021 |title= Atomically Precise Nanoclusters |chapter=Catalytic Application of Well-Defined Au Nanoparticles: Oxidation, Hydrogenation, and Coupling Reactions |publisher=Taylor and Francis |edition=1st |pages=229–254 |isbn=9781003119906}}</ref> [[Platinum group|Platinum group metals(PGMs)]] have been used in the production of [[sulfuric acid|sulfuric]] and [[nitric acid]] for centuries.<ref>{{cite web |url=https://www.samaterials.com/advantages-of-precious-metal-catalysts.html |title=Advantages of Precious Metal Catalysts |last=Trento |first=Chin |date=Dec 27, 2023 |website=Stanford Advanced Ceramics |access-date=Nov 1, 2024}}</ref> Additionally, [[gold]] and [[silver]] nanoparticles are used in [[biosensors]] and solar cells, underscoring their value in sustainable technologies.<ref>{{cite book |last1=Bhardwaj |first1=Geetika |last2=Kaur |first2=Navneet |year=2023 |title=Gold and Silver Nanoparticles |publisher=Elsevier |chapter=Chapter 3 - Implementation of gold and silver nanoparticles in sensing and bioengineering |isbn=9780323994545 |pages=83–108}}</ref>