Not counting one-off items like the Arcane Focus, there are two types of Gems: skill-based resource gems and loot-based common gems.
Resource gems are earned by anglers, lumberjacks, or miners while plying their respective trades. Resource-based gems have a flat chance of being discovered on each successful attempt to fish, chop wood, or mine. There is a 0.6% chance of finding a gem with any such action.
Lumberjacks harvest Brilliant Ambers (at 100 skill) and fishermen harvest White Pearls (at 80 skill). The remaining six gem types are obtained by Grand Master miners. While digging, the gem type is totally random - it's not affected by the underlying ore. There is an equal chance of getting any of the six miner gem types.
|Blue Diamond||Brilliant Amber||Dark Sapphire||Ecru Citrine|
|Fire Ruby||Perfect Emerald||Turquoise||White Pearl|
While some are required for certain crafted items, common gems are largely collected with an eye towards selling them for profit. When sold to NPC vendors, commom gems have five levels of values, as follows: