How much magnification required to see stylus?

How much magnification is required to clearly to be able to judge the condition of a stylus?
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Elizabeth is correct. To judge wear, you need at least 200X and up to 500X is helpful for micro types. You also need high intensity lamps on either side of the stylus. Then you have to know what you're looking for and how to judge.

The professional Audio Technica scope was 100, 300, 500X.
The later Shure scope was 200X.
I think a scanning Electron Micograph might tell you if it were worn. The problem is that using the stylus for the EM pictures destroys the stylus. If you could get certain wear states to correspond to a typical sound like Elizabeths inner groove distortion a series of worn scanning electron micographs vs nomal unworn styli would be useful.