A plate-like powder for cosmetics, powder is surface treated with a silicone gel, enhancing moldability and impact resistance of a solid powdery cosmetic composition as well as a solid powdery cosmetic composition. The surface-treated powder exhibits smooth and light touchiness, has moist usability, and excellent adhesion to skin. The surface-treated powder is blended into a powdery cosmetic composition, enhancing moldability and impact resistance of the composition and removed by an applicator. The powder is an inorganic powder, an organic powder or a composite powder, and silicone gel is obtained by hydrolyzing and condensing an organopolysiloxane containing at least a diorgano polysiloxane having reactive opposite ends by the following formula (1) and either a silane coupling agent of the following formula (2) having at least two hydrolyzable groups per one molecule or a reactive organo polysiloxane having the following formula (3) as a crosslinking agent R1R22SiO—(R22SiO)L—SiR1R22  (1) R3R4nSiX(3-n)  (2) R53SiO—(R52SiO)n-SiR53  (3).