[Uatu]

Example of gem dragons (young adult/juvenile):

Crystal Dragons
1e:
4-6 HD (20 hp), AC2, Damage 1d4/1d4/2d6 (Breath: blindness, 2/day) (Spells (30%): magic-user: 1/1, druid: 1/1) (Suggestion: 35%)
2e:
10 HD (av. 45 hp), AC 0, Damage 1d6+4/1d6+4/2d6+4 (Breath: 4d4+4 + blindness, once/3 rounds) (Spells: priest: 1)

Amethyst Dragons
1e:
8-10 HD (av. 36 hp), AC -2, Damage 1d8/1d8/5d6 (Breath: death, 2/day) (Spells (50%): magic-user: 1/2/2, druid: 2/1/2/2) (Suggestion: 65%)
2e:
14 HD (av. 63 hp), AC -4, Damage 1d10+4/1d10+4/5d6+4 (Breath: 8d8+4 + unconsciousness, once/3 rounds) (Spells: priest: 1)

As you can see, there is a significant power difference!

(Note, however, that gem dragons used to have a suggestion power that seems to have been lost in 2e.)