Grounding Crystals can be recognized as having one large sloping terminated face with eight sides. Most Crystal faces have 3, 5 or 7 sides while the Grounding Crystals have 8.
These quartz Grounding Crystals are quite rare and not easily available. Grounding is the ability to deal with practical matters in a realistic way. These crystals connect one with the earth and keep one's energies from being scattered and they can help with clarity of thought and clarity of self expression. Holding a Grounding Crystal with your thumb on the 8 sided face can help ground your emotions and holding while pressing the thumb into the face over any of your chakras can help ground and clear the chakra.
When used in meditation the Grounding Crystal can help you form a strong connection with your own higher knowledge while keep you grounded so that you can apply that information in practical terms relevant to your daily life or situation.