In Viking times small whetstones were often worn as pendants. These are reproductions of whetstone pendants found in Viking Age York. Similar pendants have been found in Kalåstad, Norway, Birka, and Gotland. They are cut from Jasper, and seem about midway between hard white and hard black Arkansas stones in action. That means they are very fine, and suitable for the honing a final edge rather than basic sharpening. They vary in color and size, but are mostly muted browns, greys', reds and greens, and about 3" tall, 11/16" wide, and 1/4" thick.
Each comes with a string and descriptive packaging. Use them dry, and clean off the clogging residue as often as necessary with water.
Imported from Sweden
CAUTION: Knife sharpening is an inherently dangerous activity. Used properly this sharpener cannot hurt you but a carelessly handled blade or pointed object can.