Upon smelting an Obsidian Shard from Obsidian Gravel, the player earns the achievement "Our Blades are Sharp".
Ordinary obsidian blocks can also be split into nine shards, using your personal crafting grid or a normal crafting table.
Obsidian shards are used in the crafting of Tauredain tools and weapons, obsidian bricks, and darts, all of which require the Tauredain crafting table. It can also be used to craft obsidian Dwarven bricks (though not the variants) on a Dwarven crafting table using four shards.
On the normal crafting table, they can also be combined into regular blocks of obsidian:
Bushland (hills) •
Cloud forest •
Jungle (clearing, edge, lake, river) •