Silica-glass crucible and production method thereof

A silica-glass crucible, comprising:

• a bottom part;
• a bottom corner formed around the bottom part;
• a lateral part extending upward from the bottom corner;
• and
• Al and Ca,
• wherein:
• the silica-glass crucible has a crucible upper-end region at an end of the lateral part opposite the bottom corner;
• the crucible upper-end region is a region extending from an upper end of the crucible downward to a distance therefrom of 5 mm or longer but not longer than a distance of a sum of an upper-end wall thickness and 10 mm;
• the crucible upper-end region has the wall thickness of 10-18 mm;
• the crucible upper-end region has a two-layer structure comprising an opaque outer layer comprising a natural-material-derived silica glass and a transparent inner layer comprising a natural-material-derived silica glass or a synthetic-material-derived silica glass;
• and
• the silica-glass crucible has a structure comprising at least three layers comprising, from a lower end of the crucible upper-end region, an outer layer comprising a crystallization-promoter-containing silica glass, an opaque interlayer which is continuously formed from the opaque outer layer of the crucible upper-end region, and the transparent inner layer.