Thanks for comments.
Mandelbulb 3d since this year has a direct ability to save the fractal as an obj. Before there was a more complicated way of saving voxel slices and using Fiji to construct an object.
I'm a total beginner with any of it so my resulting object is quite an unsophisticated crude test of Mandelbulb 3Ds direct save capability.
The surface color is some simple stacked power fractal colors using no displacement. And then followed by the reflective shader. In this case I used a refractive index that is quite high 9.8, which often gives a metallic appearance. But you don't need to use anything unusual refractive for gloss so 1.3 or 1.5 will do fine. For glossy highlights the roughness in the reflective shader should be quite a low value, such as 0.015, meaning it will be treated as a very smooth surface.
You can set the ray tracing off, which I did in this case, unless you want accurate mirror type reflection, you will still get gloss with no ray trace and it is much faster.
The quality setting of the reflective shader only applies if you give the softness a value of more than zero, such as 0.002. If you're not setting the softness above zero, (softness is very slow) then that quality value isn't used.
The other thing about glossy highlights is the direction of your sun. Some times you may need to move the sun around at a new angle to see much highlighting. Depends on the shape of the objects of course, but something quite flat may not show any gloss until the light is at one specific angle. Using a sphere as a test object you will at least get a highlight on it somewhere.