Seashells come in many lovely colors, but it’s odd to find shells that are totally black. One day while collecting shells, I found an unusual number of all-black seashells.
Well, it has to do with the mud. I originally wrote this article years ago, after walking the beach at Smyrna Dunes Park and the inlet jetty area. I mostly found black jingle shells as I recall.
Now, I have found a newer article at Shelling Boat Tours that also talks about black seashells. (Thanks Chatgpt) The tour company is located in southwest Florida, a place where everyone seems to want to live – at least over winter. Apparently they encounter black seashells down that way too.
That area of Florida is prone to some big, bad storms. Hurricanes most often only hit me – on the central east coast – AFTER they have come ashore in the Gulf. Mainly the Gulf is calm. It is a nice place for sea snails to live and therefore it’s a great place to do some shelling. Hence the newish industry of taking tourists out on shelling trips.
I agree that the best way to see what is left of the real Florida is to get there by boat. An island full of shells sounds like a fun place to explore, but where I live, I find my shells along the Indian River (in our flats boat) and Ponce Inlet (walking the beach).
Original, to Black, to Orange?
Due to the lack of oxygen when shells get buried, they turn black. That other article says that they turn orange or pink once they are back in an oxygen environment. Being unearthed and washed onshore after a storm is an example of how this could most likely happen. I always wondered about orange and pinkish shells.
In my photo below you can see the black muck that is under this clam shell. Notice that the clam is turning black as well.
Black seashells can be found anywhere really. Tides and storms can move the sand and cover shells pretty easily. After all, what can a sea snail do about that? Or the snail is gone and the shell remains, only to be tossed around, or buried deep down in the muck.
The partial lightning whelk shell below (I think) has also turned black. These shells do not start out this way. Lightning whelks are generally tan with brown stripes or light in color.
Shells are often not pretty when found. Especially if they are found in the water. They can be dark or coated with green, or with barnacles or oysters attached. Sometimes they barely look like a seashell at all, like that partially buried horse conch.
Seashells in True Color
Shells found up on the sand can be white, or much lighter in color than they were when inhabited. Buried shells might be black, and shells that are returning to oxygen may be orange or pink.
In reality, finding a seashell that still has an original pretty coloring might be the rarest find of all!
An Outer Coating vs. Ingrained Color
Sometimes out in the wild a living shell, or shell still under the water, will be covered in a dark, sometimes fuzzy, coating. That is the periostracum, or skin, which creates an outer layer over the shell. The pretty part is hidden under the skin. When the skin comes off, the shell looks as we expect a shell to look.
It is completely different from finding a truly black shell. You can see what is left of the periostracum on the horse conch and Dosinia shells below. The shell in the middle has a fuzzy or spiky skin.
After writing this post, I realize that the makers of the shells – the snails – have a pretty tough life. They create a beautiful, and perfect, home for themselves (the shell) but they are at the whim of the elements. The wind, sand, and mud can do some damage and really change things.
