Hi Racho.

If you don't mind me chiming in.

The rock hardness issue isn't an issue at all, in that what were looking at here are tooling signatures.
Some stuff is in extraordinarily hard rock, some less so, The hard stuff defies explanation.
Anyway that aside..

Tooling Signatures or Witness Marks.

The terms "machine tools", "power tools" etc. are thrown around on here seemingly without proper regard for what they actually are, how they function, and more importantly what signature they leave behind.

Three kinds of tools.
There's more and and also grey areas, but let's just look at the main three for now.

Class A.
Hand tools.
These are tools where the motive force and the positioning and guidance are entirely provided by the operator.
Examples would be a hand saw and a sewing needle.

Class B.
Power Tools.
These are tools where the motive force is provided by other than the operator, but the tool is positioned and guided entirely by the operator.
Examples would be a chain saw, a wood turning simple lathe and an electric tooth brush.

Class C.
Machine tools.
These are tools where both the motive force and the tool guidance and positioning is provided from a mechanical source.
Examples would be a machine lathe or drill press.

Hand tools A. Are hard work and although can be used with high precision if used along with precision measuring instruments.
They generally do not leave repeating signatures.

Power tools B. make life easier for the operator and can be used with precision, if like hand tools they are used along with precision measuring instruments.
They leave precise repeating signatures in the micro domain, like for example a rotating wire brush, each wire leaving its mark repeatedly, but in the macro domain produce non precision, non repeating signatures. Like the track of a powered rotating wire brush moved by hand across a surface.

Machine tools C. are often used with precision and repetition, they allow for precision placement of the tool and progression with great accuracy as they eliminate the human propensity to Err.
Machine tools often do have an initial human input but rely on a mechanical datum external to the work piece to eliminate human error.
They typically leave a high precision surface and exhibit a repeating and constant signature.

Anyways a handle on all of the above can go some way to identifying the probable techniques employed from the various signatures and witness marks we see today.