The class system is the MOHs hardness scale! I figured it out when I saw this Jamethyst picture saying how Amethyst was a 7!

-Pearls are a 2.5-4.5. Very low on the scale. The variation means that there are better Pearls on the scale. One might even say "fancier." Like a certain Peridot we know.

-Malachite is a 3.5

-Opal is a 5

-Lapis is a 5

-Garnet is a 6

-Sugilite is a 6.5

-Sardonyx is a 6.5

-Peridot is a 6.5

-Jasper is a 7

-Amethyst is a 7

-Rose Quartz is a 7

-Rainbow Quartz is a 7

-Alexandrite is an 8.5

-Sapphire and Ruby 9

-Diamonds are 10

In the guide to the crystal gems it says that gems of the same type/class do not fuse! What if because Ruby and Sapphire fused out of love, that their status was lowered? They lost their spot as a 9 and now they're at a 6 because of Garnet! If a strong gem fuses with a strong gem it makes the fusion weaker! If a strong gem fuses with a weak gem, it makes the weak gem(s) stronger! Malachite is low due to her being a fusion that doesn't work well. Sugilite is a combo of a 7 and two 9s! This means she should go down and she does! They become a 6.5! Sardonyx is a fusion of two 9s and a three! This means she should make the weak gem stronger and she does! They become a 6.5! "Fusion is a cheap tactic to make weak gems stronger!" So doesn't it also mean that it makes strong gems weaker! As shown with Garnet! Alexandrite is a combination of two 9s, a 7, and a 3! All of the gems together equal a fusion with an 8.5 (Alrxandrite)! If two 9's (Ruby and Sapphire) only made Pearl (a 3) into a 6.5 as Sardonyx. The only gem strong enough to make her a 7, as in Rainbow Quartz, would be a 10! A diamond!

Also if Rose Quartz is a 7, like Amethyst, the fusion would only be a 5 like Opal. This means that the Rose in "We need to talk" is not Rose Quartz! She's Rose Diamond!

Bismuth, the gem inside lion, is a 2.5 to a 3. Like Pearl. If Rose Diamond(a 10) was to fuse with Bismuth (a 2.5/3) the fusion would be a 7, like Rainbow Quartz! Rose Quartz (a 7) would be the fusion!