Patent ID: 8911779

Claim:
A tablet having a domed shape on upper and lower horizontal surfaces of a cylindrical plate shape, which comprises magnesium oxide particles represented by the following formula (1) as the main component, (Mg 1-x Zn x )O (1) wherein x is 0 to 0.3, the content of the magnesium oxide particles being 85 to 95 wt %, wherein: the domed shape has a two-stage structure consisting of a linear portion from both ends of a horizontal surface and part of a circle having a curvature R in a cross-section, the linear portion has an angle of 25° to 45° and a corner horizontal length of 0.3 mm to 1.0 mm, the part of the circle having a curvature R has a radius of from 7 mm to 25 mm, and a cup has a depth of 0.6 mm to 1.2 mm.