The difference between the “elegant” and “disk” is that the elegant’s ridges are fewer and broader.
The one I own was found whole- having both sides-but it has separated. You can see in the photo how the sides once fit together.
More about seashells from the Florida gulf coast:
Florida Lightning Whelk …A “left handed” seashell
Natica Lineata & Babylonia Spirata …One striped, one spotted
Lettered Olive & Golden Olive
Jingle Shells- Iridescent
Pen Shell- Can be a foot long
Jujonia -A treasure