SOLVED. An apprentice magician learns magic to save a kingdom. Spoiler ahead. [s]

[Brian]

Fantasy book about an apprentice who gets the wrong master who is stern. While with the master he makes his master a pipe. The apprentice accidently learns some alchamy and tells his master by accident, so his master dismisses him. After that he goes to his mothers house to train in magic by studing her diaries.
Spoiler
Twards the end of the book, a ghost help him find a keystone to destroy a wall

[Brian]

Also apprentice has a staff with an owl on it

[Lobstergirl, au gratin]

When did you read it?
Or when was it published?
Children's, YA, or adult?
Remember the cover?
Author female or male?

[Brian]

I read it in 1997, YA fantasy, it was the 2nd book in a series...
The apprentice stores magic in gems that looked like honey combs to him. Spoiler coming up
He had to fight an inter dimensional being that looked like a floating skull, he beat it with the help of a inter dimensional knight
Which turned out to be a beautiful girl, who was to be his love intrest, as prophesied by a gypsy

[Brian]

His mother was great wizard, also his father was a hunter. His parents house was by a lake

[Brian]

Has anybody has an idea?

[Ayshe]

The Starstone by Grace Chetwin maybe?

[Brian]

That was it.. Thank you so much!!!