Statement 2 is correct. Kodarma district in Jharkhand is renowned for its significant mica deposits and has historically been a major center for mica production and export, often referred to as the 'Mica Capital of India'.
Statement 1 is incorrect. Gondwana formations are primarily known for their extensive coal deposits in India. Natural gas reserves in India are predominantly associated with Tertiary sedimentary basins, such as those in Assam, Mumbai High, and the Krishna-Godavari (KG) Basin.
Statement 3 is incorrect. The Dharwar system of rocks is primarily recognized for its rich reserves of metallic minerals, including gold, iron ore, manganese, and copper. Petroleum deposits are typically found in younger sedimentary basins, not in the ancient metamorphic rocks of the Dharwar system.