NOVELTY - A composition comprises hydrolyzate mixture (A) containing hydrolyzate of organosilicon compound (I), and hydrolyzate of organosilicon compound having a (meth)acryl group (II), polymerizable monomer (B) having a (meth)acryl group, and photoinitiator (C).    USE - Composition is used for forming pattern for manufacturing surface treatment sapphire substrate (all claimed). Uses include but are not limited to light reflection prevention provision, light extraction efficiency improvement in light-emitting diode board, secondary battery, solar cell, fuel cell and biotechnology field.    ADVANTAGE - The composition has favorable base-material adhesiveness of cured film, excellent dispersibility, pattern transferability and productivity, and improves etching tolerance with respect to chlorine gas.    DETAILED DESCRIPTION - A composition comprises hydrolyzate mixture (A) containing hydrolyzate of organosilicon compound of formula: R11O-(-Si(-R3)(-R4)-O-)n-R2 (I), and hydrolyzate of organosilicon compound having a (meth)acryl group of formula: (H2C=C(-R3)-C(=O)-O-R6)l-Si(-(R7)m)-(OR8)k (II), polymerizable monomer (B) having a (meth)acryl group, and photoinitiator (C).    R1,R2=1-4C alkyl;    R3=aryl;    R4=aryl or 1-4C alkoxy;    n=1-10;    R5=H or methyl;    R6=1-20C alkylene or 3-10C cycloalkylene;    R7=1-4C alkyl, 3-4C cycloalkyl or 6-12C aryl;    R8=1-4C alkyl or 3-4C cycloalkyl;    l=1-3;    m=0-2;    k=1-3;and    or l+m+k=4.    INDEPENDENT CLAIMS are included for the following:    (1) formation of pattern, which involves forming a coating film by coating the composition on a substrate, and contains the composition, contacting a pattern formation surface and the coated film of metal mold win which pattern is formed, irradiating light in the state, hardening coating film, forming pattern with respect to pattern which separates metal mold from the hardened coating film, and formed in the pattern formation surface of the metal mold on the substrate; and    (2) manufacture of surface treatment sapphire substrate, which involves using the formed pattern as a mask on substrate, subjecting substrate surface to dry-etching by chlorine gas, and processing.