Gabler
Masterpiece
I recall hearing a (probably apocryphal) legend that people used to grow azaleas in abalone shells... Never heard of a giant clam shell though! It's wacky but I kinda like it.
I think we should experiment with unconventional pot choices more, sometimes they can work surprisingly well. Not sure whose it was but I saw a tree that was grown in an automotive brake drum on here, it looked really good!
I find that surprising. I would think the pH of a seashell would be too high for an azalea.