It's called an "egg separator". If you don't have one, you can crack the egg, then volley the yolk back and forth between the two shell halves over a bowl until the egg has separated.
Egg white glaze is not called by any other term, however, in American usage, it is not normally called "egg white glaze." When used in recipes, the list of ingredients would include "1 egg white," or "1 egg white beaten with 1 Tablespoon water." The directions would say something such as: "Brush top crust with slightly beaten egg white."
No, it is not a preposition. The word white is a noun (a color, or egg white) or an adjective.
The shell, unless you were looking for something more specific
Albumen is the egg white
Albumen is the egg white
white
EGGWHITE
the shell of the egg if you don't mean the white or the yolk.
Egg yolk is thicker than egg white.
The egg white is called the albumen.
The Mediterranean Sea.
Pink Lady is a cocktail drink. It contains gin, grenadine and egg white.