Сфен

Hardness: 5

A sweet, calm, and dedicated elder gem in charge of industrial arts and design. They're partners with Peridot.

Sphene used to be partnered with Topaz about a thousand years before the beginning of the story. Topaz was taken to the moon in the same battle as Peridot's old partner, Blue Zoisite, which is the reason that Sphene and Peridot eventually decided to partner with each other.