Curious Line on spruce top

[dxn2]

Please see the photo's. I recently traded for a Gibson L-130 (love it). It was discussed and accepted by me that this line/marking on the top existed. Just curious if anyone has insight as to what it might be. It doesn't run exactly with the grain. I was told the guitar sat in its case for a long period of time and that the marking was there when the case was opened.

It does not rub off, I did clean the top with some Martin guitar polish, no change.

Was wondering if it might be mold. Not a real issue for me, just a curiosity.

If there is a non-invasive way to make it go away I'd love to hear it.

Thanks,

Don

[John Arnold]

It looks like a natural coloration in the wood.

[dxn2]

Thanks for the response. The original owner suggested that it just appeared after a prolonged period of time in the case. Perhaps there was something with the wood or something that made it under the finish that just darkened over time. Again, not too worried, just curious.

[John Arnold]

Some of this coloration does tend to darken over time. It is only cosmetic.