Scrimshaw generally refers to either folk art done by sailors, especially whalers on their long voyages, or more generically, art produced by incising polished ivory or bone and adding pigment to the incisions. The heyday of scrimshaw as a folk art was the Yankee whaling period roughly encompassing the period from the beginning of the 19th century until the middle part of that century. Scrimshaw of this period is typified by sperm whale teeth embellished by designs of either a nautical nature or copies of contemporary published images. Household implements intended as gifts for the sailor's wife or sweetheart are also commonly referred to as scrimshaw. These would typically be made of whale ivory or bone, as well as other materials. Today, artists referred to as scrimshanders have rediscovered the medium, working on ancient ivories such as Eskimo artifacts and mammoth ivory. The medium lends itself to extremely finely detailed images, and today's artists can spend literally hundreds of hours on pieces small enough to be easily held in one hand.