That's a knife for working with chocolate, and not a knife MADE out of chocolate. If you thought there could possibly be no need for such a thing, think again, after checking out this piece from the LA Times
Not just any chocolate knife, but one made by Berti, the 117-year-old Tuscan artisanal knife producer known for its beautifully crafted cheese and kitchen knives for four generations. At the Berti workshop in Tuscany 20 miles north of Florence, each piece is made from start to finish by the same craftsman, an unusual holdover from another era. This is no production line, but a serious work of craftsmanship informed by the hand of one person.
That means the knives from Cotellerie Berti are more expensive than industrially produced versions. But it also means they are unique.
The beautifully designed chocolate knife looks to retail around $275, so it really is for the cook who has everything (including a large budget).