The invention relates to a light conductor having a sleeve M1 and one or more cores, wherein the sleeve M1 encloses the cores. Each core has a refraction index profile perpendicular to the maximum core expansion, wherein at least one refraction index n K of each refraction index profile is greater than the refraction index n M1 of the sleeve M1. The sleeve M1 consists of silicon dioxide and has anOH content of less than 10 ppm, a chlorine content of less than 60 ppm, and an aluminum content of less than 200 ppb. The invention further relates to a silicon dioxide granulate I, characterized bya chlorine content of less than 200 ppm and an aluminum content of less than 200 ppb, each relative to the total weight of the silicon dioxide granulate I. The invention further relates to a silicon dioxide granulate II, characterized by a chlorine content of less than 500 ppm and an aluminum content of less than 200 ppb. The invention further relates to a method for producing silicon dioxide granulates I and II according to the invention and for producing a quartz glass body, a light conductor, and a fiber optic cable.