The Tirunelveli district in Tamil Nadu, India has many geological features, including hard rock formations, crystalline limestone, and minerals.

Hard rock formations

1. Charnockite: An acidic to intermediate type of hard rock that covers almost 99% of the district
2. Granite gneisses, amphibolites, and granulites: Rock types found in the Sivanmalai Syenite Complex

Minerals

1. Crystalline limestone: A notable economic mineral found in the district
2. Multi-color dimension stone: A notable economic mineral found in the district
3. Garnet and ilmenite sand: Notable economic minerals found in the district
4. Graphite, mica, and gemstones: Minor occurrences of these minerals have been reported in the district