Smoky Quartz is one of the most powerful energetic cleansing and grounding crystals.  This ability to clear negative energy allows for a strong grounding connection to the Earth.  This strong energetic stability is particularly helpful for those who suffer from depression and anxiety.  It's also helpful for protection and detox of Electromagnetic fields and radioactive exposure. 
This piece weighs 4lbs 6 ounces and measures 6.5 inches tall and 4 inches at the base.