The state of Oaxaca is home to some of the finest Mexican crafts, and one of the most representative, unique, and popular items produced in this region, is the beautiful barro negro, or black clay pottery. Famous for its color, sheen, and intricate designs, black clay pottery is one of the most popular styles of pottery in Mexico, which dates back to the pre-Columbian era. Black clay pottery is a traditional method of making pottery that was used by the Zapotec Indians in Pre-Hispanic Mexico. The color of the black clay pottery is due to the properties of the clay, which is found in the valley surrounding the region. In fact, the mere process of separating the clay from the rest of the soil can take up to a month. After this process is completed, each piece takes an average of 20 days to complete. Traditionally, the clay is molded and spun by hand without the use of a wheel or any other modern tools tool. Once shaped, the pieces are set out to dry in a well-insulated room for a lengthy period of time. If the piece is to be polished, then it is polished when it is almost completely dry. The surface of the piece is lightly moistened and burnished using a quartz crystal, which produces a lacquer-like silver luster. This is also the stage when decorative accents are added using sharp knives and other hand tools. The pieces are then fired in underground pits or above-ground kilns, using wood fires that heat the pieces to temperatures between 700-800°C. When done, the polished pieces are a shiny black color and the unpolished pieces have a grey matte finish.