A TABLET WHICH COMPRISES SOLID PARTICLES, ESPECIALLY MAGNESIUM OXIDE PARTICLES AS THE MAIN COMPONENT AND HAS EXCELLENT SHAPE RETENTIVITY WITH EXTREMELY LOW SUSCEPTIBILITY TO WEARING AND CHIPPING. THE TABLET HAS A DOMED SHAPE ON EACH OF THE UPPER AND LOWER HORIZONTAL SURFACES OF A CYLINDRICAL PLATE SHAPE, WHEREIN THE DOMED SHAPE ON EACH OF THE UPPER AND LOWER HORIZONTAL SURFACES SATISFIES THE FOLLOWING REQUIREMENTS (A) , (B) AND (C) IN THE CROSS-SECTIONAL SHAPE INCLUDING THE CENTER LINE OF THE CYLINDRICAL PLATE SHAPE: (A) EACH CORNER HAS AN ANGLE OF 25 TO 45°, (B) EACH CORNER HAS A HORIZONTAL LENGTH OF 0.30 TO 1.0 MM, AND (C) THE CUP HAS A DEPTH OF 0.6 TO 1.2 MM. (FIGURE 1)
