The gems are the most powerful objects in the Encantadia world, so the article name deserves some thought.
For the English version, 'gem' is preferable as opposed to 'gemstone', since it is shorter yet they mean the same thing. 'Fire Gem' would also be preferable as opposed to 'Gem of Fire' and the like, for the same reason.
As to the article name: should it be 'Gem' or 'Brilyante'? I think the article name should at least be 'Brilyante', even though 'gem' should be used in the content.
Five or one? Should each gem have its own article, or would they be better understood if presented jointly, side-by-side?