What we perceive as consciousness through our mind is contained in Atman only. Atman is pure consciousness. It is the cause of consciousness which is played by the "mind" in the human body.
Kena Upanishad Chapter One:
IV
That which speech does not illumine, but which illumines
speech: know that alone to be the Brahman (the Supreme Being), not
this which people worship here.
V
That which cannot be thought by mind, but by which, they say,
mind is able to think: know that alone to be the Brahman, not this
which people worship here.
VI
That which is not seen by the eye, but by which the eye is able
to see: know that alone to be the Brahman, not this which people
worship here.
VII
That which cannot be heard by the ear, but by which the ear is
able to hear: know that alone to be Brahman, not this which people
worship here.
VIII
That which none breathes with the breath, but by which breath
is in–breathed: know that alone to be the Brahman, not this which
people worship here. Ordinarily we know three states of consciousness
only – waking, dreaming and sleeping. There is, however, a fourth
state, the superconscious, which transcends these. In the first three
states the mind is not clear enough to save us from error; but in the
fourth state it gains such purity of vision that it can perceive the
Divine. If God could be known by the limited mind and senses, then
God–knowledge would be like any other knowledge and spiritual science
like any physical science. He can be known, however, by the purified
mind only. Therefore to know God, man must purify himself. The mind
described in the Upanishads is the superconscious mind. According to
the Vedic Sages the mind in its ordinary state is only another sense
organ. This mind is limited, but when it becomes illumined by the
light of the Cosmic Intelligence, or the “mind of the mind,” then it
is able to apprehend the First Cause or That which stands behind all
external activities.