Copper, silver, or gold MC cartridge coils?

Copper coils seem to be the most popular.

Silver coils seem to have the general trait of warmer midrange and extended high frequencies, by those that prefer them.

Copper has lower mass than silver, and much less mass than gold. Better transients?

Silver has the best conductivity, followed by copper, then gold.  Gold has the best corrosion durability.

Can we draw any conclusions as to the type of sonic traits and preference of each type?

Any preferences and why your choice of type, or is there no big differences sonic wise?
The key is not the wire in the cartridge but how the cartridge reacts with your arm, table, and phono stage. You want to pick the best cartridge for your system and that can be a challenge but a big reward when the magic happens. You also want to play your choices for at least 6 album sides because low output moving coils take a long time to relax.
The closest I got to comparing coil materials in a more or less level playing field was hearing three different vdHul Colibri’s in the same arm (Reed 3P 12" Cocobolo) in immediate succession: XCP (copper coils, plastic body) XGW (gold coils, wood body) and XPW (platinum coils, wood body). As far as I know there never was a Colibri with silver coils.

In my system I had a clear preference for the platinum coil version (a limited series and no longer made). It struck a nice balance between the fast, dynamic, punchy sound of the copper version and the smoother, more refined presentation of the gold coils, while adding a superior 3D stage neither of the others could match.

Disclaimer: the Colibri as a breed are known to be temperamental and the word goes they all sound different. So a similar comparison with three different samples might yield a different outcome!

BTW: this comparison was done prior to the introduction of the current Stradivarius and Signature versions. These new systems may have very different characteristics and be more consistent than the previous series.

I have a Airy 3 Gold, silver base to mount, after my Airy 3 Silver, silver base, goes sour (which is soon, after 3 years of use).

Also have a Airy 3 copper, silver base that has 1.5 years of use.

I have two identical VPI JMW 10 arm wands on my TNT 3 that I use.

I will post my opinion later on the gold coil ZYX.

At some point early in the history of the ZYX Universe, which according to legend is a "special" model originally developed for USA distribution only, one or more reviewers opined that the copper coil/low output version of the UNIverse was the best sounding of the optional versions, which included, in addition to the copper/low output version, copper/high output, and silver coils with low or high output.  (Output is either 0.24mV or 0.48mV, depending on the choice of "low" or "high".)  That notion took root among audiophiles, and nearly everyone (including me) bought the copper/low output version.  I don't know the story that goes with all the later versions of the UNIverse, of which there are now too many to keep track of, at ever increasing price points. Other than that one instance, I never thought much about purchasing a cartridge based on the conductor used to wind the coils of a cartridge.  Like Raul says, it is the overall design that counts far more, in my opinion too.  This notion is supported by the fact that there are good and bad sounding cartridges with either copper or silver coil windings.  Gold is more rarely ever used, except by van den Hul and one other brand mentioned above.  I think in considering the "sound" of a gold coil, we have a difficult time divorcing ourselves from the subjective biases surrounding "gold". Gold "feels" warm and lush, just to use the word.

Koetsu "silver clad copper" is almost for sure not different from "silver-plated copper".  I have never liked the sound of ICs made from silver-plated copper, no matter how pure is the composition, because it sounds more bright and edgy to me in my systems than either pure copper or pure silver. On the other hand, Koetsu cartridges, even the ones with silver-plated copper coils, never sound bright and edgy, which brings me to the question: to what degree does the nature of the wire used to wind the coils in a cartridge or in a transformer affect the SQ of the output?  I doubt it is valid to think about that without reference to the physics of a coil of wire. For this I refer to Intactaudio's post above.  Dave knows more about the electronic behavior of a signal in a coil or transformer winding than any of the rest of us can even dream of. I wonder whether his remarks about the sound of copper, gold, silver pertain to wire in a coil or linear wire.  Maybe also Dave could comment on the physical state of the audio signal in a coil serving as part of a transducer, as in a cartridge or a SUT or an output transformer.  Folks pay big bucks for silver windings in a SUT or output transformer; are the results worth it?
The following will offer a description of the Urushi Cartridge Bodies as well as a description for the Silver Clad Copper Coils on a Koetsu Urushi.

There is no such thing as THE URUSHI – because Koetsu delivers different models – leaving out the Koetsu Urushi Vermilion, which I will talk about in a minute. All of the other Urushi cartridges are technical equal – what differs is the amazing lacquer artwork in the traditional Japanese Urushi fashion. Some of the models are made with very old techniques, and they are named after the Japanese cities in which these techniques were invented – examples are the Wajima and the Tsugaru. Others use a more modern twist to the old traditional techniques, the Sky Blue comes to mind. Urushi lacquer is a natural product which is won out of tree resin. It needs a long, long time to get fully dry and as it gets dry it gets harder and harder. Underneath the Urushi lacquer – you might guess it already, we will find – a rosewood body….so the Urushi carts use the same material and body form factor as the Rosewood Signature – the difference is the lacquer technique which gives the body a different behaviour regarding mechanical energy transmission and resonances! Technically there is also something new to discover….we still have a 6n pure copper coil but in this case it is cladded with silver. The cladding process could be explained if you imagine your girlfriend or wife putting on her sexy nylon stockings….. So the silver is not melted upon the copper nor is it a hybrid material mixture – it is still pure copper with a very thin cladded silver layer on top. The magnets circuit uses still smarium cobalt material as we get it also from the entry level Black Goldline, but – SURPRISE!!!! we will have now treaded mounting holes – THANK YOU KOETSU!!!!!