Draw a conical frustum with Graphics3D?

I would like to draw a conical frustum with Graphics3d. Any idea of a simple method?

The documentation recommends:

Graphics3D[{CapForm["Butt"], Tube[{{0, 0, 0}, {0, 0, 1}}, {1, 1/2}]}]

Cheers,

Marco

That is exactly what I was looking for. Thanks.