The present invention relates to a plate-like powder for cosmetics, which powder is surface treated with a silicone gel and has effects of enhancing moldability and impact resistance of a solid powdery cosmetic composition as well as a solid powdery cosmetic composition containing such a powder. The surface-treated powder exhibits smooth and light touchiness, has moist usability peculiar to the silicone gel, and is excellent adhesion to skin. When the surface-treated powder is blended into a solid powdery cosmetic composition, it enhances moldability and impact resistance of the solid powdery cosmetic composition, is readily removed by an applicator, and affords good usability. Preferably, the powder is an inorganic powder, an organic powder or a composite powder thereof, and the above silicone gel is obtained by hydrolyzing and condensing an organopolysiloxane containing at least a diorgano polysiloxane having reactive opposite ends represented 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. €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒR 1 R 2 2 SiO-(R 2 2 SiO) L -SiR 1 R 2 2 €ƒ€ƒ€ƒ€ƒ€ƒ(1) €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒR 3 R 4 SiX (3-n) €ƒ€ƒ€ƒ€ƒ€ƒ(2) €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒR 5 3 SiO-(R 5 2 SiO)n-SiR 5 3 €ƒ€ƒ€ƒ€ƒ€ƒ(3)
