That stone is about 3.5" long. It is a very hard sharpening stone that is more of a decoration than a practical sharpener. Ragnar, a fellow that runs ragweedforge.com sells these as "Viking Stones". Apparently they are cut from actual sharpening stones that the Vikings moved mostly to the UK.
Good story and good "hard Arkansas" type stones, but mostly decorative.
The leather braids are all done in kangaroo...my normal "medium" of choice. Thanks for the kind words.
I am still working out my mixed leather/paracord ideas for a call. I have one of Watkin's Swamp Bores on order that deserves a nice lanyard.