This article is from the Final-Fantasy and other Square Soft Games FAQ, by firstname.lastname@example.org (Nick Zitzmann) with numerous contributions by others.
Return to the Great Glacier area. The best path to take is to go south
from the snowy wasteland. This will eventually lead to an area with hot
springs (lakes with steam rising from them). Go down to the edge of the
left lake and touch the water, you will hear a sound effect. Now, leave,
and return to the woman. She will fight you, and if you win the battle,
you'll receive the Alexander Materia.