Search:

Looks like we're all settling in on it being a soft (contemporary hard) Arkansas...

If the stone is closely cut to a 4" x 2" x 1/2" dimension, as your first photo would seem to imply, then it...

That last pic does make it look like a soft Arkansas. Some of them can be pale, particularly the new ones called "hard Arkansas" (actually a soft Ark following the older system of description).