It starts with the raw casting. That nub you see on the bottom is where the sprue for casting is attached.
The first step is to file away the sprue...
Then I sand down the rest of the sections starting with a course grit, up to a fine grit. At this point, it is almost to a shiny polish.
Finally, to get that soft brushed texture, I use this polishing wheel and gently press the casting against it as it's spinning.
Last but not least, I create the chain and assemble it to the pendant.