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Collection of relevant buzzwords for further googling:

These days the "plastic" look of computer generated imagery is mostly caused by not wanting to spend more time and money on cheap TV cartoons. The state of the art in computer graphics is "physically based rendering", meaning that the software accurately models the physics of light in as much detail as the user of that software desires.

The effects that you observed are modelled with something known as "Bi-Directional Reflectance Distribution Function", usually abbreviated to "BDRF". If the BDRF is allowed to vary with wavelength, then materials like Bismuth are covered as well ("spectral rendering").

Translucency is caused by light traveling through solid matter and being scattered there. Even material that we think of as opaque can permit light to travel a short distance through it, without being completely absorbed. If that light happens to exit that same surface again in a nearby place, there is a substantial influence on the overall look of that material. The most common application of this is "subsurface scattering" to more accurately model the look of human skin.

Translucency in general is a subset of light interacting with the medium it's travelling through. Effects like mist, fog, "god rays" / "volumetric shadows", are all caused by light _not_ travelling unimpeded in a straight line.

And finally there is the modelling of the wave nature of light, to render interference or diffraction. These effects are usually subtle and rare. To my knowledge, no professional rendering software implements general wave rendering. However, things like soap bubbles and iridescent butterfly wings are everyday phenomena, so the renderers usually provide some tricks to approximate the effect in plausible ways.

Small correction: the abbreviation for bidirectional reflectance distribution function is BRDF, not BDRF (maybe helps when searching for more info).

Thanks! I am just an interested dilettante, trying to guide other laymen to a point where they can begin asking the right questions.

It should be it:


https://en.wikipedia.org/wiki/Subsurface_scattering

Direct surface scattering (left), plus subsurface scattering (middle), create the final image on the right.
Actualy I can't say that this feels realistic. It somehow reminds skin not mineral.


This is better.  If slight fractality and natural imperfection would be added this would look just like real marble statue. Subsurface scattering:


Alsou


Ha ha, these names is like BSDM

There is some scientical papers about this. If they are needed they can be accesed by first ever piratic scientic site Sci Hub . This seems legitimate becouse some scientis had called a species in name of creator of that site. "  Idiogramma elbakyanae Khalaim, sp. n.  The species is named in honour of Alexandra Elbakyan (Kazakhstan/Russia), creator of the web-site Sci-Hub, in recognition of her contribution to making scientific knowledge available for all researchers."
https://jhr.pensoft.net/articles.php?id=12919