I am considering buying a set of Mohs hardness scratch pens (aka hardness picks). As a hobbyist the price is quite high, starting at 300 USD and upwards for a complete set. I can accept this price if I can expect them to do their job for a lifetime, or at least for a decade.

I assume that the tip of these picks are machined to have a sharp edge, probably a single point.

All cutting tools, like drill bits or saw tooths loose this sharp edge with use, so I assume the same will happen with these scratch pens. But when googling for this, I havent found a single source that talks about how to maintain/sharpen these pens, and I haven't found a single source that talks about how long they last or if they will need replacing.

So let me try and put this into a few questions:

  • How long can I expect such a pen to last and how long will it do its job well?
  • Do people sharpen or otherwise maintain their scratch pens?
  • Do people replace their scratch pens?
  • 3
    $\begingroup$ One thing you could do, if you do not get a satisfactory answer here, is to contact the manufacturers of the pens & ask them how the pens should be maintained for optimal use. $\endgroup$
    – Fred
    Jul 19, 2022 at 11:54

1 Answer 1


I'm sure there are cheaper versions for it. But to answer your question, it's more of a investment for a lifetime and no need to worry about buying new ones in the next 20-30 years.


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