
ANSWER: What you have is a 19th-century grease lamp made of stoneware. Farmers used these lamps, fueled by animal fat, in their homes. They often threw away early, less refined versions, as better ones appeared on the market.
Stoneware is one of the hardy perennials of the American antiques trade. Each year, auction houses, antiques shops, and flea markets sell thousands of pieces at prices from $25 to several thousand dollars. The record price stands at $15,000 for a rare 1773 stoneware inkstand. Only a handful of pieces fetch prices in that stratospheric range.
Stoneware is a heavy, hard pottery that resists odors and tastes and won’t absorb water. The first American stoneware appeared in the last half of the 18th century, and for more than 100 years people used stoneware vessels to store and transport foods and liquids. It was essentially the 19th-century version of Tupperware. When glass and metal containers came into common use, people stopped using it.

As with many other antiques, age isn’t the main reason in determining the price of an object—its decorative qualities are far more important. An attractive late-19th-century jug will fetch more at auction than a homely Revolutionary-era piece. Most stoneware forms, such as jugs, crocks, jars, churns, and pitchers, are very simple and vary only slightly in shape and design. Decoration, if any, tends to be sparse. When a potter decorated his pieces, he often used simple floral, bird, or scroll motifs painted on the stoneware in three basic colors—blue, brown, or black. The most common stoneware style has a gray-glazed background with blue decoration. Such run-of-the-mill pieces, which represent about 90 percent of the stoneware available today, are generally worth less than $50.
Because many stoneware items look alike, the most valuable pieces are those with unusual or imaginative decoration. A rare form, such as your stoneware grease lamp, or an odd-sized piece, an exceptionally large crock, for example, can be worth several hundred to several thousand dollars.