Some frame materials scratch fairly easily -- carbon is probably among the easiest, along with bamboo.

Aluminum and titanium seem to be in the middle.

Hardened steels would probably be near the top.

What are the numbers though? Exactly how soft and scratchable is carbon?

There are several different hardness scales. Does anyone have hardness ratings for any of the frame materials?

It's surprising this isn't more of a consideration for those buying multi-thousand dollar carbon frames, when it is a major concern or consideration in smartphone and jewelry design, even at the less expensive levels. It relates to how well they keep their looks over time -- how well they hold up to abuse and accidents, and to typical daily use and wear and tear.

Exactly how much difference between frame materials? Is 953 harder or softer than the latest Gorilla Glass, quartz or topaz?