Obsidian

Obsidian is a very hard, glass-like, dark mineral. In Guild Wars, Obsidian may refer to:
 * Obsidian Shard - a type of rare crafting material
 * Obsidian Armor - a type of armor, high-end, crafted from Obsidian Shards (among others)
 * Obsidian Flesh - an Earth Magic skill
 * Obsidian Flame - another Earth Magic skill
 * Obsidian Flame (Guild) - an NPC guild