POO PIC: dark gray??

Rebecca

This poop definitely looks dark gray to me. No change in diet, she is 4mo and takes Gerber good start gentle pro (has for 2 months). I have a visit scheduled Tuesday but I’m wondering if I should take her to urgent care before then? Thoughts?

***UPDATE: pediatrician said the gray looks like it’s due to undigested formula and suggested switching to a soy formula as well as starting prune juice for constipation.