- Joined
- Mar 26, 2002
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- 3,397
Let's see:Originally posted by spiraltwista
I thought ferric oxide was rust, which is softer than Iron?
Google gets me to :
http://www.ameritech.net/users/knives/mohs.htm
Mohs Hardness Scale (Revised)---
Diamond ==> 15
green silicon carbide ==> 13
garnet ==> 10
aluminum Oxide (corundum) ==> 9
green chromium oxide ==> 8.5
*red rouge (ferric oxide) ==> 6.5
*steel file => 6
knife steel ==> 5.5
copper penny ==> 3.5
http://www.mfa.org/_cameo/frontend/material_description.asp?name=ferric+oxide&language=1
"An insoluble dark red powder that occurs naturally as hematite. Red iron oxide has been used since antiquity as a permanent red pigment in paints and glazes (see red ocher). In the late 1700's, ferric oxide was manufactured as a red pigment. This synthetic, intense red pigment with a uniform particle size is now called Mars red. Ferric oxide is also found in the form of rust. Rust is a corrosion product that readily occurs on iron and some steels in the presence of oxygen and moisture. Fine powdered ferric oxide, called jeweler's rouge, is also used as an abrasive for glass, precious metals and diamonds. Ferric oxide is also the most common material used in magnetic coatings on audio and video tapes. "
http://www.reade.com/Products/Oxides/ferric-oxide-crystalline.html