Shilajit is a little hard to explain, and it is almost a panacea in some circles. There are entire books on fulvic acid, one of the constituents of shilajit.
Shilajit is created by run off in the Himalayas that deposits organic material into the crevices and fissures of stones. When the snows melt and the sun hits the rocks, a resinous substance softens and exudes. It is sometimes called bituminous pitch or asphaltum. It is dark red to brown to almost black in color and very bitter and is said to enhance the efficacy of any other formula taken.
Sanskrit texts refer to shilajit as the "conqueror of mountains and destroyer of weakness." Shilajit has a high mineral content; so prized was the herb in ancient times that no major disease was believed to be curable without this asphaltum. Despite the very ancient history of use of shilajit, very little is really understood about its exact origin, even whether it is a plant material or mineral. Most likely, its resinous nature is due to the presence of mosses that have contributed to the formation of shilajit. The Ayurvedic forms of shilajit are purified using traditional processes spelled out in ancient texts. The Russian shilajit or mumijo is washed but raw.