The grinding media used in ball mills can have a faceted appearance. When new, flat spots or points could increase impact pressure to improve the rate at which things got crushed in the mill, but I suspect they just naturally develop when the stuff you are crushing is partially harder than the shot.
Things to look for are asymmetric angles and numbers of facets and variations in shape and concavity/convexity from face to face, typically if something is made to be polygonal it will be regular, uniform, symmetric to a greater degree.
I don’t think ingots have ever had facets…
This ball from an old mine is 2.5” ~6.4 cm across: