1899 IHC Struck Through Something?

To me, it looks integral to the planchet and not post-mint
Gold? That sure would be interesting. It could be an area of the planchet with more tin?

Yeah...I've seen a few IHCs, and can't say I've seen one like that.
If brass, you'd think it would tone with the rest of the coin?

Interesting - and I'm not sure what to make of it. Here is one of my Indians with a 'gold-like' metal struck through it, certified by NGC as such. I had a couple of gold coin experts look at it, and they both said with authority that it's not gold. But I still don't know what it is but would like to show you one example of a known metal strike through ... http://indiancenterrors.shutterfly....pictures/187

This one still has me intrigued. Brass is a distinctive color vs. gold alloys.
Have you ever read about this 1906 IHC--struck on a gold planchet?

The reflectance of gold alloys is definitely unique, probably owing to its density.
Wait...you metal detect for gold, right? Well...no need for me to say anything on this subject.

I appologize for not being able to find the link right now, but either PCGS or NGC has a relatively new service that they can tell you the composition of coins, and even metal from strike thoughs. It costs an additional $75 to the regular costs of having it graded and slabbed, so it'll run you about $100. If it were cheaper, I could justify sending a few of mine in for that service - but it would, however, conclusively answer the question at hand.

A microscopic analysis would probably reveal whether it is part of the alloy or whether it was an extraneous bit of metal rolled into the bronze cent stock. I do find it interesting that it has a "comet-like" appearance with an obvious beginning at the hair curl and fading as it trails away towards ES. That would seem to fit the profile of foreign metal rolled into the stock and smeared as the stock is rolled out to proper thickness.