Graphite is normally found in the form of flakes in metamorphosed rocks. The rocks in which graphite is found are rich sources of carbon and other carbon-containing compounds. Graphite is a carbon allotrope and is also obtained from veins and in pegmatites.
Graphite deposits in metamorphic rocks are caused by the reduction reactions on sedimentary carbon compounds in rocks in the process of metamorphism. However, some deposits of graphite are found in igneous rocks and in meteorites in different regions. In such deposits, the mineral is found with other related minerals, such as quartz, calcite, mica and tourmaline. Graphite from meteorites is often found deposited in small crystals with troilite and silicate minerals. The mineral is also found deposited with meteoritic iron, in which case it is referred to as cliftonite. Graphite is deposited in large quantities in metamorphic rocks, and the graphite from such large deposits is used in industries for making pencil lead and lubricant. According to statistics from the U.S. Geological Survey, there were about 1.1 million metric tons of natural graphite produced in the world in 2012. The main producers and exporters of graphite in the world in this period were China, India, North Korea and Canada.