So here is my card:
I hope it's obvious that this card is embossed with nautilus shells. That's what's from the sea.
I embossed an aqua card base with a Spellbinders Embossabilities sea-themed embossing folder. They I dusted the whole card liberally with Perfect Pearls, to give it that mother-of-pearl sheen.
The sentiment is a vellum sticker, which I pasted onto more of the same aqua cardstock (Recollections brand), cut down to size, and them mounted with dimensional adhesive.
I'm pretty happy with the way it turned out.
So there it is, my first card challenge.
I also am working on a card for the Play Date Cafe Challenge which involves shells, so if that turns out well, I'll post it here as well.
UPDATE: I just wanted to say Thank You for all the lovely, kind comments on this card. It means a lot to have people appreciate my work. Thank you.