Smoky quartz is, I think, the best grounding stone. It will literally pull your energy downward, helping you focus, stay grounded, and complete tasks (including balancing your checkbook). I have personally seen people energy change from wearing/carrying smoky quartz to not. It is a powerful stone. Do not underestimate it's properties.
To find out more about this stone's mental, emotional, and physical properties, check out the Crystal Report that is included and emailed with all purchases or join Crystals for Your Health.