Iran's primary natural resource export is petroleum and petroleum based products like 'oil and natural gas'.
Iran has a large number of crude oil reserves because of which it is today the major producer and exporter of oil.
The Iranian government has entered into trade agreements with several nations for exporting oil.
Oil exports contribute maximum to the economy of Iran. Iran also has massive reserves of natural gas and therefore is a major 'exporter' of 'natural gas' as well.