I apologize for the lack of clarity in the photos but there are these black dots peppered in a line along the lower section of the throat of my shoe (the last two photos are from the other shoe of the same pair) and I’m uncertain whether or not this is the start of mold growth or if this is just the tannins reacting to friction in some way.

 I figure you guys would recognize innocuous spotting from friction or the application of wax/oils as opposed to spotting from mold growth or something else. The thing that has me chiefly confused is that dots this big cannot be found anywhere else on the shoe; on both shoes dots this big are only found on the inner part of the throat, nowhere else inside the shoe, nowhere else outside the shoe.

The thing that has me concerned is that I originally applied mink oil to the shoe, including just that inner part of the throat, and not long after learned of the disadvantages of doing so and so removed it best I could with saddle soap, replacing it w a coat of heavy duty LP Obenaufs. 

I really don’t think it could be mold in any other circumstance, but the fact that I had applied mink oil (with all the organic fats/ sugars that entails) I may have prompted mold growth in j that specific region. This being said I took multiple photos with and without flash to get clear on this bc I just don’t know leather well enough to know whether these are imperfections in the leather, something friction related, or something like staining of pores from the application of wax/ oils. Any advice would be greatly appreciated. Thank you 

Is this line of peppered black dots mold, darkened tannins, or something else