Abstract: Provided is a high-quality Group III nitride crystal of excellent processability. A Group III nitride crystal is produced by forming a film is composed of an oxide, hydroxide and/or oxyhydroxide containing a Group III element by heat-treating a Group III nitride single crystal at 1000° C. or above, and removing the film.

Abstract: A semiconductor light-emitting device member excellent in transparency, light resistance, and heat resistance and capable of sealing a semiconductor light-emitting device without causing cracks and peeling even after a long-time use is provided. Therefore, a semiconductor light-emitting device member that comprises (1) in a solid Si-nuclear magnetic resonance spectrum, at least one peak selected from a group consisting of (i) peaks whose peak top position is in an area of a chemical shift of ?40 ppm to 0 ppm inclusive, and whose full width at half maximum is 0.3 ppm to 3.0 ppm inclusive, and (ii) peaks whose peak top position is in an area of the chemical shift of ?80 ppm or more and less than ?40 ppm, and whose full width at half maximum is 0.3 ppm to 5.0 ppm inclusive, wherein (2) silicon content is 20 weight % or more and (3) silanol content is 0.1 weight % to 10 weight % inclusive is used.