Colons: semi-colons;

Indicates a pause between two main clauses.

Colon: introduces a list or an explanation.

Semi-colon; ends a sentence and can act as a comma if commas are already present

Rule

Incorrect: My mom sent me to the store with a long list of items toe clippers, foot cream and hair wax.

Correct: My mom sent me to the store with a long list of items; toe clippers, foot cream and hair wax.

Incorrect: Some teachers in this hallway are Mrs. Phillips, English, Mr. Jackson, History and Mrs. Fritz, Writing and theater,

Correct: Some teachers in this hallway are Mrs. Phillips, English; Mr. Jackson, History and Mrs. Fritz, Writing and theater,

(http://www.gcsu.edu/writingcenter/colonrules.htm)