Editing Noble metal (section)

== Meaning and history ==
While lists of noble metals can differ, they tend to cluster around gold and the six [[platinum group metal]]s: ruthenium, rhodium, palladium, osmium, iridium, and platinum.

In addition to this term's function as a compound [[noun]], there are circumstances where ''noble'' is used as an adjective for the noun ''metal''.  A [[galvanic series]] is a hierarchy of metals (or other electrically conductive materials, including composites and [[semimetal]]s) that runs from noble to active, and allows one to predict how materials will interact in the environment used to generate the series. In this sense of the word, [[graphite]] is more noble than silver and the relative nobility of many materials is highly dependent upon context, as for [[aluminium]] and [[stainless steel]] in conditions of varying [[pH]].<ref>Everett Collier, "The Boatowner's Guide to Corrosion", International Marine Publishing, 2001, p. 21</ref>

The term ''noble metal'' can be traced back to at least the late 14th century<ref>{{cite web|url=http://dictionary.reference.com/browse/noble+metal|title=the definition of noble metal|website=Dictionary.com|access-date=6 April 2018}}</ref> and has slightly different meanings in different fields of study and application.

Prior to Mendeleev's publication in 1869 of the first (eventually) widely accepted periodic table, [[William Odling|Odling]] published a table in 1864, in which the "noble metals" rhodium, ruthenium, palladium; and platinum, iridium, and osmium were grouped together,<ref>Constable EC 2019, "Evolution and understanding of the d-block elements in the periodic table", ''Dalton Transactions,'' vol. 48, no. 26, pp. 9408-9421 {{doi|10.1039/C9DT00765B}}</ref> and adjacent to silver and gold.

<gallery widths="165px" heights="165px">
File:Chalcopyrite-199453.jpg|<div align="center">[[Chalcopyrite]], which is copper iron sulfide (CuFeS<sub>2</sub>), is the most abundant copper ore mineral</div>
File:Ruthenium a half bar.jpg|One half of a ruthenium bar.<br>Size ~ 40 × 15 × 10&nbsp;mm<br>Weight ~44 g
File:Rhodium powder pressed melted.jpg|<div align="center">Rhodium: 1 g powder, 1g pressed cylinder, 1 g pellet.</div>
File:Palladium (46 Pd).jpg|<div align="center">Palladium</div>
File:Acanthite - Imiter mine, Jbel Saghro, Tinghir, Drâa-Tafilalet, Morocco.jpg|<div align="center">[[Acanthite]], or silver sulfide (Ag<sub>2</sub>S)</div>
File:Osmium crystals.jpg|<div align="center">Osmium crystals, 2.2 g</div>
File:Iridium-2.jpg|<div align="center">Pieces of pure iridium, 1 g, size: 1–3&nbsp;mm each</div>
File:Platinum crystals.jpg|<div align="center">Crystals of pure platinum</div>
File:Gold nugget (Australia) 4 (16848647509).jpg|<div align="center">Gold nugget from [[Australia]], nearly 9,000 g or 317 oz</div>
File:cinnabar09.jpg|[[Cinnabar]] or mercury sulfide (HgS) is the most common source ore for refining elemental mercury
</gallery>