Silver and Gold

You have your colors of the visible spectrum ROYGBIV, and white which is all colors together, and black which is no colors.

But where does gold fit in? Is it a shade or hue of yellow? (I don’t know the proper term to use). And is silver some version of white?

It’s a version of yellow. In RGB it’s usually a mix of just red and green, with a bit more red. Other characteristics like the reflection of light and a smooth surface help us identify it.

Color is the wavelength of light. The visible spectrum above shows “bands” of wavelengths. But other colors are the result of more than one non-adjacent band of these wavelengths reflecting together. Brown, for example, is mainly red and green, plus a little bit of other wavelengths to give vairious shades of brown.

Also, there are other properties such as “shiny” or “dull” that are not colors, they are not due to variations in wavelength, they are variations on how the light gets reflected from a surface.

According to the Life Science Library volume *Matter, * copper and gold are the only colored metals.

So is silver a type of yellow too?

Does Mercury not count?

If you took a gold object, and put it in a completely featureless environment with completely uniform lighting, it would just look yellowish. Do the same thing for silver or most other metals, and it’ll just look gray. You identify them as instead gold and silver because you see the reflections of light sources or other objects in them.

As an example, here’s a picture of some gold bars. In that picture, the gold doesn’t show up as any one color: Portions of it look like a pale grayish yellow, and portions look like a darker yellow, and parts look brown or even almost black, depending on what it’s reflecting.

It’s even more dramatic if you have a single large flat sheet of it. Take a picture of a large, smooth, flat sheet of silver, and you’ll end up with a picture of a person holding a camera.

No.

Advanced telescopes need mirror surfaces that are manufactured and polished to incredible precision, and that are, well, mirrors - they reflect virtually all light straight back uniformly.

The Hubble telescope mirrors were made of glass. However, the James Webb telescope will have mirrors manufactured from Beryllium, a silvery metal. I’m sure that if you were to look into one of these smooth polished Beryllium mirror surfaces it would not look “metallic”, it would be indistinguishable from a high quality glass mirror.

http://jwst.nasa.gov/mirrors.html

They are the only ones you are likely to encounter, and which aren’t debatable as to whether they are “colored” or not - they are considering all the other metals to be some variant of gray, silver or white, which they don’t consider “colored”. Caesium is pale gold colored, but elemental caesium can catch fire spontaneously in the air, and will react explosively not only with liquid water, but with ice down to a temperature way below zero. It’s liquid at slightly above room temperature. You may have seen a small sealed sample of it in a classroom, but probably nowhere else.

Of course there’s also brass and bronze, if you consider alloys to be “metals”. Though I’m not sure if there are any colored alloys that don’t contain gold or copper.

I don’t. I am speaking strictly about elemental metals.

*The Hubble telescope mirrors were made of glass. However, the James Webb telescope will have mirrors manufactured from Beryllium, a silvery metal. I’m sure that if you were to look into one of these smooth polished Beryllium mirror surfaces it would not look “metallic”, it would be indistinguishable from a high quality glass mirror. *

I think this is a bit misleading - the mirror substrate is glass, but the reflecting surface deposited on the surface of that glass is aluminum with an extremely thin coating of magnesium fluoride over that.

I’d guess not, certainly not any common ones. BTW, another metallic element which is arguably “colored” is bismuth. It’s sometimes claimed to be slightly pink.

(Many bismuth compounds are certainly pink, though the “pink bismuth” (trade name Pepto-Bismol) preparation you buy at the drugstore has had red food coloring added to it to enhance it. The bismuth subsalicylate in it wouldn’t make it that bright pink by itself.)

Bismuth is apparently slightly pinkish-silver in its elemental form.

Of course, more famously, it’s a good deal more colourful than that, but only due to oxides on the surface:

Fun fact: the color of gold (and cesium) is due to relativistic effects in the electron bands. It brings two particular electron orbitals closer together, which moves their bandgap into the visible (blue) spectrum, and this absorption gives them a yellow hue.

Nitpick…black means undetectable colour. There’s heaps of signal level in between zero and undetectable… But since colour is basically what our eyes detect it to be… I guess that will do.

There can be issues with "what our eyes detect it to be " . Bring a moon rock to earth… in regular room light, or outside twilight or night time… it might appear “black”. but we can all see the moon is white…Because the test for colour is done when there is enough light on it to get a reading of colour from the reflection/emissions… Against the night sky, the sun light, at the level of daylight, is reflecting off the rock and being easily detectable a having a white spectrum. But in the reduced light conditions of twighlight or something, the reflection falls below what our eyes can detect… fake black. The crystals in the rock absorb a lot (same as the ocean can look black even on in strong sunlight.)
Back to silver then…

Silver (the element) and other metals (of same look) are often reflective, a mirror. Our brains detect the mirror effect and calls it silver. Our brains detect and correct for shadows and very low angle of incidence reflections, so when we see “silver” on the expected spots on objects, our brains detect that its a reflection (Due to low angle of incidence … Well its not flagged as something unusual , which is to say our brans correctly ignore it… )If we see a mirror, which is a material that relfects even at 90 degree angle of incidence, our brains work out “hey, thats reflective at a high angle of incidence! be careful of that !”

Elemental colours ? Well there are other colours associated with some other metals.

Cobalt
rust (of course its the oxide hydrate.)

carbon black ?

Having simulated gold bars in a 3-D modeling program, I can tell you from experience that gold isn’t just about the color. If you don’t have the reflectivity, it looks like a yellow brick. If you want something to look like gold, it has to be yellow-ish (you don’t need the color exactly right) and it needs to be reflective.

Similarly, silver is just a light gray plus a bunch of reflectivity.

Lead and lithium are both slightly blue-ish; but you have to look at them very quickly, or the oxide layer will spoil your view.