The colon creates expectation in a sentence: something significant always follows it. Its specific uses are outlined in the links to the left.
An Explanatory Phrase that Follows a Complete Sentence
-- I've led a sheltered life: I've gone from one shelter to another.
-- Pain stood in the way like a sheet of glass: you could walk through it, but not without a certain noise.
An Appositive
Note: An appositive is a word or phrase that identifies the noun or pronoun preceding it.
--Besides sniffing cigars and snapping suspenders, there was one sure thing to be
on the tycoon's agenda: money.
-- I've led a sheltered life: I've gone from one shelter to another.
-- Pain stood in the way like a sheet of glass: you could walk through it, but not without a certain noise.
A Series or List When It Follows a Complete Sentence
--Such are the blessings of which I am fully aware
: a mother with wild young hormones; a pasture with satyrs and centaurs; a view of
the roving heavens from my trundle bed.
--These are the reasons for his absenteeism: a fear of furniture; an aversion to numbers and dollar signs; a snakebite on his
chin.
Chapter or Verse in Biblical References
--Noah's long, wet story begins in Genesis 5:28.
-- Work Cited:
Gordon, Karen Elizabeth. The New Well-Tempered Sentence. New York: Houghton Mifflin, 1993.