2014-D Ghost Of Jefferson - A Badly Damaged Nickel

Thin rims leans me towards a corrosive as the cause.

With the thin rims and pourous, pitted surfaces I'm on the "coorosive environment" train.
The darkness seems like that could be from being dug.

Ok here are the vital stats:

Weight is 4.69 g
Diameter is 21.2mm
Thickness is 1.9mm

That is under weight. Jefferson nickel tolerance is 4.806 grams to 5.194 grams. So, Acid?

Hey Dearborn, a note about your calipers. I had a similar expensive set - also stainless steel - and scratched a coin with it. I then saw some plastic digital ones at Harbor Freight - $10. They work great.
https://www.harborfreight.com/6-in-...r-63586.html

I'll start a series of soaks using the polarity ladder - so starting today, it'll get a 24 hour soak in H2O (distilled).
followed by 24 hours each of:
Tap Water
99% Isopropanol (aka as isopropyl alcohol)
Acetone
Xylene
Mineral Oil

Remember Safe Soaking Rules:

Never rub the coin with your fingers or a cloth while wet to avoid micro-scratching.
Let the coin air dry on a clean, soft microfiber towel or paper towel between each solvent step.
Test low-value coins first before applying any chemical process to collectible or historic pieces

After the water soak, I'll get it under my scope for some close up images..

That is a possibility too as the 'black top' asphalt can get a tad warm here in the summer months (which starts in March and ends in November for Phoenix)

ADOT (Arizona Dept of Transportation) has a program ongoing now to remove all asphalt from the highways in Greater Phoenix Metro area cause it has been melting or getting soft.