The Narmada Banalingam is found in Madhya Pradesh by the banks of the Narmada River. It is a natural forming stone and it is associated with Lord Shiva. Its presence in the home is said to bring good luck and worshipping it is said to invoke the blessings of the Supreme God. You can worship it when you pray to Lord Shiva to enhance its positive energies in your home. The black stone is shaped like a Shiva lingam and has a smooth texture. Buy on the Giri UK store.