Sapphire
Sapphire is one of the common gems in UO. It spawns as loot.
A 2008 March survey indicated a value of 98 gold per sapphire, though some tinkers collect them for crafting purposes.
Sapphire is found on Jeweler vendors. It is also used in imbuing. Sapphire can also be bought off of Jeweler vendors. It is also an imbuing ingredient.