# Why are most metals grey/silver? Why are gold and copper NOT silver? **URL:** \ **Category:** Factual Questions\ **Created:** [October 17, 2022, 12:42am UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351 "2022-10-17T00:42:50Z")\ **Posts on this page:** 19\ **Page:** 2
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 18, 2022, 9:08am UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/21 "2022-10-18T09:08:15Z")
Is there not also a metal that is faintly bluish/lilac in colour? (the metal itself, without oxidation) I seem to remember that there was one, but can’t recall what it was. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [October 18, 2022, 3:15pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/22 "2022-10-18T15:15:03Z")
I think a few metals have a hint of blue, but they’re still mostly gray. I did find that tantalum and cadmium can appear a bit bluish. Cobalt, oddly, does not look blue at all to me in pure form, even though it’s famous for being used to make blue dye. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [October 18, 2022, 3:15pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/23 "2022-10-18T15:15:54Z")
Yeah, it’s quite yellowish. I still don’t know WHY most metals are grey and only three aren’t. Interestingly, copper and gold are in the same group, group 11, but cesium is not. Cesium is in group 1 with other scarily reactive metals. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [October 18, 2022, 3:37pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/24 "2022-10-18T15:37:53Z")
> [@RickJay](#): > > I still don’t know WHY most metals are grey and only three aren’t. It was alluded to in the first response. In metals, their outer (valence) electrons are shared in an electron “sea”. This is why metals are comparatively good conductors, and some are excellent conductors. This electron sea has density oscillations with a characteristic frequency, and these oscillations interact with the field of EM radiation to either transmit or reflect depending on frequency of the EM radiation. [Some details here](https://en.wikipedia.org/wiki/Plasmon#Role). When we do the math / chemistry / quantuming, we find that for almost all metals the characteristic frequency is greater than visible light, so, to our eyes, they reflect all frequencies completely. When their surfaces are very smooth they may function very well as a mirror. If we had an evolutionary reason to differentiate elemental metals, we might have evolved (again) a UV-sensitive color cone in our eyes. Then they would appear different shades. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 18, 2022, 7:25pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/25 "2022-10-18T19:25:57Z")
> [@RickJay](#): > > Cobalt, oddly, does not look blue at all to me in pure form, even though it’s famous for being used to make blue dye. Cobalt blue is a mixture of cobalt oxide and aluminum oxide. So the color of the pure metal is irrelevant. Similarly, the pigments with chrome in their names are compounds and not metalic chromium. OTOH, Prussian blue is made out of real live Prussians. 🙂 ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 18, 2022, 8:50pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/26 "2022-10-18T20:50:11Z")
I think you mean real _formerly_ live Prussians. 😉 ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [October 19, 2022, 12:28am UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/27 "2022-10-19T00:28:17Z")
Depends how quickly you use their parts. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [October 19, 2022, 9:42am UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/28 "2022-10-19T09:42:51Z")
> [@LSLGuy](#): > > I think you mean real _formerly_ live Prussians They’re live _when the pigment is made._ ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [October 19, 2022, 12:19pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/29 "2022-10-19T12:19:44Z")
Osmium metal is faintly blue. I think its tetroxide is also strongly colored, but I’m talking about the bare metal itself. As an aside, aluminum does oxidize fast, forming a stable solid and very hard oxide, alumina – also known as sapphire if it’s a single crystal. This creates a special vulnerability. If you get gallium metal, even a droplet, onto a piece of aluminum, the aluminum is doomed. Gallium is very much like aluminum, except that its melting temperature is around room temperature. The aluminum dissolves into the gallium. Like all liquid solution, the aluminum diffuses around in the gallium. But atoms that happen to make it to the surface oxidize very quickly. Trouble is, this nice hard oxide is now on a liquid, and can’t form a protective coating, so the oxidization keeps going. A drop of gallium can destroy a big chunk of aluminum, and short of cutting the contaminated aluminum away, or putting the whole deal in an anaerobic environment, there’s no stopping the process. For this reason, IIRC, gallium is not allowed on aircraft. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [October 19, 2022, 1:11pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/30 "2022-10-19T13:11:17Z")
> [@MrDibble](#): > > They’re live _when the pigment is made._ They make a commotion that really distracts you from your work, though. > [@Napier](#): > > If you get gallium metal, even a droplet, onto a piece of aluminum, the aluminum is doomed. Gallium is very much like aluminum, except that its melting temperature is around room temperature. The aluminum dissolves into the gallium Video of this rather arresting phenomenon. The fun starts at 3:00. [![](https://img.youtube.com/vi/IgXNwLoS-Hw/maxresdefault.jpg "Amazing - What Gallium does to an Aluminium Can") ](https://www.youtube.com/watch?v=IgXNwLoS-Hw) ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [October 19, 2022, 2:36pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/31 "2022-10-19T14:36:59Z")
> [@Napier](#): > > also known as sapphire if it’s a single crystal. Or ruby. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [October 19, 2022, 2:42pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/32 "2022-10-19T14:42:47Z")
Or pulling apart aluminium padlocks after using a gallium “key” [![](https://img.youtube.com/vi/8cCNOFQyTX4/maxresdefault.jpg "This Key can DESTROY a lock!") ](https://www.youtube.com/watch?v=8cCNOFQyTX4) ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 19, 2022, 4:41pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/33 "2022-10-19T16:41:34Z")
Reminds me of firehouse slang. They have what they call a “universal master key.” It can open any door. It’s actually a 250lb musclehead firefighter with a big axe. And gasoline powered chain saws & circular saws in back-up for the really hard cases. I was interested to Google [Buy gallium] and see it was easy to get and not very expensive. Remind me not to buy any aluminum padlocks. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [October 19, 2022, 5:29pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/34 "2022-10-19T17:29:37Z")
I wouldn’t be too concerned. A thief has to know it’s aluminum and/or bring gallium just in case. It’s not very likely in practice. They are much more likely to bring bolt cutters or just chance upon a bike or whatever that the owner forgot to lock. ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [October 19, 2022, 5:33pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/35 "2022-10-19T17:33:58Z")
> [@Mijin](#): > > They are much more likely to bring bolt cutters or just chance upon a bike or whatever that the owner forgot to lock. Of course, if it’s a bike, they’d have to be careful not to get it on the bike or they destroy what they tried to steal. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [October 19, 2022, 6:11pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/36 "2022-10-19T18:11:04Z")
> [@LSLGuy](#): > > I was interested to Google [Buy gallium] and see it was easy to get and not very expensive. Remind me not to buy any aluminum padlocks. $29 for about half an ounce on Amazon. Which isn’t much, but it’s enough for a cool experiment. ---
**Author:** ![california\_jobcase](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@california\_jobcase](https://boards.straightdope.com/u/california_jobcase)\ **Post date:** [October 19, 2022, 6:22pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/37 "2022-10-19T18:22:23Z")
Mercury does the same thing. ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [October 19, 2022, 6:42pm UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/38 "2022-10-19T18:42:30Z")
But mercury isn’t a solid at room temperature\* and is much more toxic. I wouldn’t recommend it for amature experiments. \*granted, Gallium isn’t solid in a _warm_ room, but that’s half the fun anyway. ---
**Author:** ![EnolaStraight](https://avatars.discourse-cdn.com/v4/letter/e/41988e/32.png) [@EnolaStraight](https://boards.straightdope.com/u/EnolaStraight)\ **Post date:** [October 25, 2022, 3:44am UTC](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351/39 "2022-10-25T03:44:00Z")
Compared to other silvery metals, zinc is…blue-ish. [Previous page](https://boards.straightdope.com/t/why-are-most-metals-grey-silver-why-are-gold-and-copper-not-silver/973351.md?page=1)