Some spells on DominiaMUD use specific, or colored, mana. There are five different colored manas: green, blue, red, white, and black. Some classes can use the tap ability to gain it through the environment. Others don't have this ability and must use gems to get it. There are mobs for each colored gem.

Green Mana
Exiled Druid - Uncut emerald
Faerie Noble - Emerald figurine

Blue Mana
Prodigal Sorcorer - Flawed sapphire
Illusionary Forces - Lapis-Lazuli pendant

Red Mana
Goblin Shaman - Smoky ruby
Chandler - Ruby Figurine
Anarchist - Hematite pendant

White Mana
Repentant Paladin - Huge pearl
Lost Bride - Alabaster pendant

Black Mana
Headless Horseman - Jet crystal
Buried - Onyx talisman
Chest - Dark Seed