I show you a mystery-
they are three yet one-
three has great value
beauty and clarity-
one is amorphous-
worthless and ugly-
two is flaky yet smooth as velvet
and cabbages and kings
have they in common.

Three is sought by royalty-
and single ladies as well-
while one is the object
of a chimney sweeps ire.
Though one and two can beget three
there is no regret-
when a housewife scrubs away one
with three on her finger-
or for artists that create with two in their hand.

Many have sought to change-
one and two into three-
but only a fool
would seek to change three.
One is spelled with an S,
number two with a G-
and number three is spelled with a D-
yet all are a form of the element C.

Surely by now you must know
what they are.