Confirmed Theory
Gem Theory is now a confirmed theory! Congratulations to the theory's author,!
Gem Theory
Ocean Gem Lapis Lauli Regen
Theory Information
Date of Publication May 27, 2015

So, my theory is simple. The gems are not unique. What I mean by this is that each gemstone has an number of gems bearing it, similar to races on earth.

Firstly, think back to the return when Jasper criticizes the crystal gems. "A lost, defective pearl!" "A lost defective pearl." "A." So, I find it strange she refers to Pearl as A lost pearl, not a lost defective gem. Also, don't you think it would be difficult to have a functioning society only named after the gems?

Also, the popular diamond theory. The diamonds may be a seal demonstrating some form of leadership capability. Ruby and Sapphire may be weaker gems, Amethyst could just be the generic kindergarten creation, or it could be gluttonous or something similar. So, I think that your job or social standing on gem world is decided by what gem you are, and also where it is placed. Both Peridot and Pearl have head gems (I know this has been brought up before) And are thinkers, Amethyst eats a lot but also is caring, thus heart gem, And Garnet thinks with her fists, plus this denotes symmetry, Ruby and Sapphire.

So that's my theory. Did I forget something? If so, let me know!

Confirmed Theory

It is hinted in the episode "The Return" and confirmed in "Back to the Barn" that there are more than one of each gem.