There are black obsidian mirrors which are extensively used for gazing and which are formed of highly polished slabs and/or highly polished half-spheres.
This obsidian, inducing creativity in all endeavors, has also been known as the asking stone. One my ask questions aloud, and will receive a whispering answer with respect to the topics of how one's relationships, finances, health issues, and career choices are influenced by the universal energies that rule one's space-time continuum. These also assist one to reach only and always for the positive, leaving behind all travails, annoyances, and trivialities of each moment.
It has further been used to assist one in work with the third eye with respect to gaining answers to one's purpose and
one's lessons which one had predetermined to fulfill prior to entering the body this time.
Excerpt from Melody's Love Is In The Earth, ISBN 9780962819063. Used with permission of Earth-Love Publishing House LTD.