LuvThemKnives on YouTube is constantly test the Rockwell hardness and if the advertised steel is what they say it is for different Chinese knife makers. There is also a reference table of all the test performed.
I actually have experience using a rockwell hardness gauge myself when in a mechanical engineering classes. It will give you the rockwell hardness, but can’t identify the steel used. I would imagine a chemical analysis would be required. I tested my Benchmade McHenry marked as having 154CM steel. I am sure it was 154cm, but the hardness was lower than I expected. That knife still has the mark left by the gauge. To the best of my memory, it had a small needle like part on the gauge and hydraulic pressure was applied until the needle started moving into the metal when it would click and give the gauge reading. It would leave a very small mark. I do not know how you might test the actual metal, but would guess it might require filing and testing the shavings, but I am guessing. I know I have heard that Buck knives use of 440C with the heat treatment they used would usually result in higher rockwell hardness than other manufacturers could achieve from the same steel. In fact, I think I read they are getting 440C hardness from 420HC steel. I had a buck knife but it was lost or stolen.
Good info, thank you. I would bet that analyzer is not in the budget range of ordinary people. Such a specialized device would likely be produced in very small quantities. I would not be shocked to see a 20,000 dollar price tag on such a device. PS, after writing this I saw a used xrf alloy analyzer by a different brand used on ebay for 3900 dollars. I would say that is more than a casual collector will be enticed to spend. It is cool that such devices exist though. Even used, the near 4000 dollar price means it is out of my price range. If they were to create a device to very quickly put a polished mirror edge on a blade…that, I might be interested in. If after spending 2 hours trying to sharpen M390, or some other super steel, and it looks like the diamond infused sharpener is not removing any material, it is a good guess that it is truthful. I would not even waste my time trying to use any non diamond stones to cut that steel. The s110 is in need of someone more skillful than me to sharpen it. It is just too hard, both in Rockwell hardness and effort needed to sharpen it to interest me in having knives with these ridiculously hard to sharpen steels. M390 and D2 are about as hard as I wish to tackle. That is with a KME sharpening system capable of putting a scary sharp mirror edge on anything. It would do it even on those, but it still would not be easy.
I also wanted to say, it was the LuvThemKnives youtube channel that I saw the reviews of both of my CH knives. I think the channel actually linked to the CH store on Aliexpress, but I am not sure. One of the knives arrived fine, the other actually took forever and sent the wrong knife….a cheap piece of crap. I went through hell trying to get a refund, but finally gave up. Then, and I kid you not, over a year later a package came that I had no idea what it was or where it came from, and it was my knife…the right one. Where it hid for over a year is still a mystery. I refused to order anything through Aliexpress for 2 years at least. The seller had finally agreed to the refund, but Aliexpress never sent it. It was all ok after I received the right knife, but I no longer trusted their return policy. Both of the CH knives though, I love, and trust me, the light weight titanium and extreme hardness of the M390 steel verified the authenticity. Both were titanium scales, but 1 was M390, the other was S35VN. It appears that CH has since started making their knives from G10 scales an D2 steel to be a more budget knife. That was not the case then. Both knives are on bearings with crazy good actions. The M390 is model 3507 reviewed here https://www.youtube.com/watch?v=2B6ZMeRUiMg The other was the 3002 reviewed here https://www.youtube.com/watch?v=EK0-BnubRms&t=601s