What is the equivalent in F# of the C# default keyword?

I found this in a blog: “What does this C# code look like in F#? (part one: expressions and statements)”

C# has an operator called “default”
that returns the zero-initialization
value of a given type:

default(int) 

It has limited utility; most commonly you may use
default(T) in a generic. F# has a
similar construct as a library
function:

Unchecked.defaultof<int>