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That pretty much sums it up!

Nobody can be dead certain were the coloration comes from, but we know it could be really bad!

Me, nooo!
I've already got a cracked TI Spartacus... I would look for some thing else.

Hmm, I don't think that's from heat.
The "rainbow" seems to repeat itself, my guess would be some oil or other solvent on the blade.

Edit; I do remember I've seen this type of rainbow on blades...