Titanite

Titanite is a rare resource in Astroneer. It occurs in nodes of tall, cylindrical lime green crystals.

Source
Titanite can be found on the following planets:

The gives 1 Titanite for every 2, up to 4 total for 8.

Uses
Titanite is used to craft the following items:

Media
Titanit Titanita Titanite チタン石 Титанит