PROBLEM TO BE SOLVED: To provide an ultraviolet-shielding particle coated with silicon oxide that can exhibit desired ultraviolet-shielding properties even when applied to an aqueous cosmetic, an aqueous composition containing an ultraviolet-shielding particle coated with silicon oxide and a cosmetic containing the same.SOLUTION: Provided is an ultraviolet-shielding particle coated with silicon oxide, in which the surface of an ultraviolet-shielding particle is coated with a silicon oxide film, wherein, a composition, which comprises: 46.0 pts.mass of a gel obtained by mixing water and an alkyl-modified carboxyvinyl polymer 0.2 pts.mass and adjusting the pH to 6.0 with 2.5 mol/L sodium hydroxide the ultraviolet-shielding particle coated with silicon oxide 50 pts.mass and glycerol 4.0 pts.mass, is mixed with decamethylcyclopentasiloxane at a mass ratio of 1: 1, and it is dispersed for 10 minutes by ultrasonic, to obtain a liquid mixture. After the liquid mixture is allowed to stand for 20 hours, an oil phase of the liquid mixture has 360 nm transmittance of 100%. And, when the composition 10 pts.mass and carboxyvinyl polymer gel 90 pts.mass are mixed and the mixture is held between slide glasses for observation by light microscopy, the aggregate observed has a particle size of 50 μm or less.SELECTED DRAWING: None【課題】水系の化粧料に適用されても所望の紫外線遮蔽性が得られる酸化ケイ素被覆紫外線遮蔽粒子、酸化ケイ素被覆紫外線遮蔽粒子含有水系組成物及びそれを含む化粧料の提供。【解決手段】本発明の酸化ケイ素被覆紫外線遮蔽粒子は、紫外線遮蔽粒子の表面が酸化ケイ素被膜で被覆されてなり、水とアルキル変性カルボキシビニルポリマー0.2質量部を混合し、2.5mol/L水酸化ナトリウムでpHを6.0に調整したジェル46.0質量部、酸化ケイ素被覆紫外線遮蔽粒子50質量部及びグリセリン4.0質量部からなる組成物とデカメチルシクロペンタシロキサンとを1:1の質量比で混合して超音波で10分間分散処理した混合液を20時間静置後、混合液の油相の360nmの透過率が100%、組成物10質量部とカルボキシビニルポリマージェル90質量部とを混合しその混合物をスライドガラスに挟んで光学顕微鏡で観察される凝集物の粒子径が50μm以下。【選択図】なし
