There are three of them!
“The three supernals, namely,
The Doctrine and Literature of the Kabala (page 312)
Kether, Chokmah and Binah,
are the three fountains of metallic things.
‘The thick water,’
that is mercury,
is Kether,
salt is Chokma,
and sulphur is Binah.
Those are the three principals of alchemists. …
Chessed, Geburah and Tiphoreth
as before to silver, gold and iron,
Naztech, is tin,
Hod is copper,
Jesod is lead,
while Mulkath is the ‘metallic woman;
‘Luna of the wise,’
and the field into which
the seed of secret minerals ought to be cast,
that is,
the ‘water of gold’.” …
The Kema or magical squares of the planets
are given in connection
with the seven metals,
but not always correctly.”