Looking for surface that leaves a distinct mark on contact

Hello all,
I've been googling all day, but I can't seem to find an answer to my question. I'm looking for a material that makes a distinct mark on contact
with it's surface, but fades or can be wiped away. The contact will be made with a metal implement, not a marking implement (pen/pencil/whatever). I.e. the mark should come from the surface of the material. Also, the material should be strong enough not to tear with light pressure.
Any experts or "people in the know" want to shed some light on this mystery material? Does something like this even exist?
Thanks,
Jason Reposa
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

made
I.e.
mystery
Are you thinking of the "blue" that engineers and fitters use when machining or scraping bearings?
--
Terry Harper
http://www.terry.harper.btinternet.co.uk /
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

machining
I'm just looking for a firm material that marks upon pressure by metal. If you're talking about Prussian blue oil paint, then no. I want something that marks the material without the aid of colored paint.
Thanks for your reply,
Jason
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jason Reposa wrote:

There is a film sold by sensorproducts inc., i think developed by Fuji. There are embedded microcapsula with red color. So depending on the pressure it changes the color. There are several pressure ranges available.
Look at http://www.sensorprod.com
Markus Greim Germany
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jason Reposa wrote:

Lead will leave a smudge on a contacting surface.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

ok.. compared to the other posters ideas this is different and probably all wrong: Phenolphtaleine in water with pH 8-9 and higher is dark red. CO2 from the air slowly reduces the pH thereby leaving the solution colorless. So much for the fading part. Little (polymer/wax/?) bubbles filled with the solution might snap under pressure. If for example traces of sodiumhydoxide are placed under the bubble (not dissolved in the solution of phenolphtaleine) the solution won't turn red until the bubble bursts. It definitely is a one time only use and difficult to realize, but who knows.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.