Green Cancel Questions On A Buff 5c Jefferson

I'm working on breaking down an album for ebay and came across this rather decent looking stamp. On close inspection I see some damage/repair at the bottom. So there's that. But my question is on the cancel. Since green is pretty unusual I checked Scott and wow - there's a $900 premium for green. So that throws me for a loop. I'd like to understand 1) why green is coveted - is it just rarity or some other reason. and 2) I'd want to have some confidence that it is legit.

So I'm looking for anyone who might be able to educate me and potentially identify the cancel or narrow it down in some way. Thanks.

Green is a rare ink color for cancels, but ...
yellow + blue = green.
The cancel looks green when struck over the printed image.
The cancel looks blue along the left margin on the white paper.
Cancel is from Cincinnati, Ohio.
It appears to be a blue cancel to me.

Agreed - and this Cincinnati cancel is very well known in dark blue as is the case here.

Ha! Thanks. Good explanation. Thanks for identifying the cancel.