D&D 5E Fizban's dragon "ratings"

[Ancalagon]

Hello

So for a long time now, we've had (a bit like the order of giants) a "rank order" of dragons has been present. It isn't absolute - an ancient black dragon is far, far more dangerous than a red dragon wirmling! But, all things being equal, a red dragon is more powerful than a black dragon. And it's always 5 ranks:

The order is, from least to most powerful:

Chromatic: white, black, green, blue, red
Metallic: brass, copper, bronze, silver, gold
Crystal: crystal, topaz, emerald, saphire, amethyst

But what about dragons that don't fit in this? The deep, moonstone and others? Is there a similar pattern?

 

[R_J_K75]

Heres a pattern I noticed. I just read the Green Dragon parts of the FR Draconomicon, 2E MM, 3E Draconomicon , 4E Draconomicon and Fizbans and was very surprised how much was reprint, not verbatim in all cases but almost.

 

[Yaarel]

Judging by the Creature Lists: Challenge Ratings at the highest tiers:

CR28 metallic greatwyrm
CR27 chromatic greatwyrm
CR26 gem greatwyrm



(Heh, I just realized on analogy with the other two adjectives, it should be "gemmy dragon".)