A crystal with an eight sided face is called a Grounding crystal. They are rare. Grounding crystals help you deal with practical matters in a logical and clear-headed way, attuning to Earth energies and preventing your thoughts from jumping around. An ungrounded person does not like to deal with the practical or realistic aspects of life, and can benefit from using a grounding crystal. When used in meditation, they allow you to form a strong connection with higher knowledge, but keep you grounded so you can apply that information in a practical sense. Some signs that may help you recognize the need for a grounding crystal include lack of concentration, feeling reluctant to tackle tasks that need doing, and the feeling that you are working flat out but not getting anywhere.