I've read that the Hindus hold the conch shell to be pure and virtuous, attributes which would certainly lend it to use in religious practices. But how did this shell become such a powerful symbol?

It's my opinion, and please note that this is only an opinion, that the mysterious sound of the sea when you hold a conch shell up to your ear may have contributed to its adoption in religious rituals.

I own a conch shell that once belonged to my grandmother. I'd guess it's between 80 and 100 years old, and the I can still hear the ocean in it. Such an unexplained and seemingly magical phenomenon would have been the perfect catalyst for its adoption into religious use.

Even today, there are several theories on why the ocean can be heard in a conch shell. A 1928 German study asserted that the conch animal living in the shell set up a reverberance to drive off and destroy intruding micro-organisms. This theory is perhaps reflected in the Indian folk medicine belief that the sounds from the conch shell can cure malaria, leprosy, epilepsy and gastrointestinal problems. It's certainly worth a try should one have one of those diseases, cheap and painless.

But this still doesn't explain why the sound lingers in the shell. A more modern explanation is that our own ears are producing the sound.

No matter. Early peoples would not have had any scientific explanation for the sound and would have thought it a magical gift from their gods. So that's what I think. What do you think?