We are the Crystal gems

Jasper

I warped back to the temple. Two hours, as was my deal with Peridot.

I looked around, when something caught my eye on the porch.  I stepped out to investigate.

Lapis was sitting on the railing with a small blue... gem?

"Lapis, who is this?" Lapis turned to face me, a smile on her face.

"Oh, hello Jasper! This is Sapphire." Just as I had feared.

"I- I'll be right back!" I yelled as I ran down the beach.

"Wait, Jasper! " Lapis yelled after me.

"Can't be happening, can't be happening! "

Where in the Universe did Lapis find Sapphire, of any gem?

Sapphire was a defective diamond, from a while back.

Blue diamond, one of Yellow's past sisters, tried to make the ultimate representation of herself.

She took small chips of her gem, combined them with Black sapphire's and created Sapphire.

She was small and defective, and Blue diamond demanded she simply be called Sapphire, and hidden from the public eye.

I guarded her room, and fell in love with her. But she rejected my feelings, giving me the cold shoulder.

Literally, she froze my shoulder once.

I though carefully, where could she have been? Then it hit me.

Diamonds had perfectly triangular gems. Most other gems  had round gems, with some exceptions.

Sapphire had a round gem with a triangle facet.

Just like the one on Garnet.

"But who did she fuse with?" Then it hit me. That little runt of a Ruby.

This wouldn't be pleasant.