I'll say it was! awesome! I thought I had one too today until I picked it up and it fooled me, dang creek optical illusions. But there's no denying the one you found.
Yup! especially the gray color ones under water mixed in with pebbles and stones, saw a lot of them yesterday and you have to pick them all up just in case geez!
Yep me to and the ones here turn black just like the flint in the creek. I always touch them with my stick just in case. Once it was a point so I always hope.