That's quite the difference- and some very interesting info, Charles! Excellent job!
Q: Does the Whelk's carnivorous diet enhance the color of the pearl, and if so, to what extent?...
Q: Obviously, the colder temperatures lead to finer crystallization of organic material (well, assuming that the snail's metabolic processes slow down in cooler temps which I think is a fairly safe idea); does the colder temperature enhance the flame pattern of the pearl?
A1: Crowned Whelk,Lightning Whelks & Channel Whelks are the Carnivores here. Being a diver i get to see odd things underwater. I have watched them eat Quahogs, Steamer Clams etc.. I believe that since they eat shell to get to the meat, they inherit a different structure of a pearl created in a whelk vs Conch. That is as far as what i can see. The Crowned Whelk here in New England have a very Orange Interior shell. The Conch from around the Florida keys has a pinkish interior and eats a softer diet of sea weeds and such ( Vegetarian ).
A2: I have found on this subject that the Whelk does not have a flame pattern at all, but a "Cat's Eye" Affect. I have found 2 others from here that also had the Cat's Eye affect.
I may not be an expert yet, but i reasearch daily and also observe these in the wild. Quite an experience.