Abstract: To provide a diamond rendering reflective light off a table goldenly brilliant by making a proportion thereof symmetrical at any place viewed from an upper face, a side face or a bottom face, a first reference line, a second reference line crossing the first reference lines at a right angle and third reference lines equally dividing segments defined by an intersection of the first reference line and the second reference line into four equal parts, respectively, are provided. A first arc line intersects these reference lines. An approximately regular hexadecagon shaped table is established by line segments defined between these first intersections of the reference lines with the first arc line. Fourth reference lines dividing sectors defined between the third reference lines into two equal parts and a second arc line concentric with and larger than the first arc line, are provided.