Budding amethyst should be obtainable blocks. Like yes you can farm amethyst in geodes but it could be more convenient to have it in your own base. Since amethysts doesn’t have any gamechanging use or purpose in the game, there's no risk in making it obtainable in survival.

Like you could use amethyst blocks or amethyst clusters for decorations iin builds or have a large supply of hardened glass.

(I'm not pointing out that amethysts are useless, I'm just saying that it doesn’t have any definitive groundbreaking purpose like others.)