Titanite is the main crafting and upgrade material in Dark Souls, and reappears in Dark Souls II playing a somewhat smaller role.
Standard Titanite is used for the basic upgrade path, which grants weapons or armor a simple stat increase at each upgrade level. It is also required to create and upgrade Raw, Lightning, and Crystal weapons.
It comes in four sizes: Shard, Large Shard, Chunk, and Slab.
Green Titanite is used to create and upgrade Magic, Divine, and Fire weapons up to +5. It comes only in Shards.
Blue Titanite is used to upgrade Magic weapons past +5, and to create or upgrade Enchanted weapons. It comes in two sizes: Chunk and Slab.
Red Titanite is used to upgrade Fire weapons past +5, and to create or upgrade Chaos weapons. It comes in two sizes: Chunk and Slab.
White Titanite is used to upgrade Divine weapons past +5, and to create or upgrade Occult weapons. It comes in two sizes: Chunk and Slab.
Twinkling Titanite (one size only) is used to upgrade certain weapons and armor, such as the Black Knight weapons and the Giant armor set, that cannot be otherwise upgraded. Although these items are termed "unique," many of them can be obtained multiple times in one playthrough.
It is always dropped by Crystal Lizards, and sometimes by Man Eater Shells and Stone Guardians.
Demon Titanite (one size only) is used to upgrade certain rare weapons, primarily those crafted with boss souls. It is always dropped by Prowling Demons.
Dark Souls II