Shell material is, as the name suggests, a material made from natural shellfish shells. It is mainly used for buttons on jackets, shirts, blouses, and similar items. The color and texture vary depending on the type of shell used. It is a material characterized by its distinctive luster. The main types of shell buttons are Takase, black butterfly, brown butterfly, and white butterfly. While it is heat-resistant, it is weak against impact and very easy to break, so careful handling is required. Because it is a natural material, the pattern and color vary slightly from piece to piece.