The common jingle shell (Anomia ephippium) is easy to identify, but maybe not from a distance. While walking along the shoreline, spotting a black shell could mean you’ve found just about anything. Any shell can end up turning dark gray or black in color if the conditions are right.
On my latest visit to the beach, I gathered some jingle shells, of which most were black, as you can see in my photo. One is somewhat silver, and another has bits of lighter tan, which means it still retains some of it’s original color.
But jingle shells don’t start out as black. Just like the lightning whelk below, shells turn black because of sea and sand conditions. According to a comment left on another blog, The Ocracoke Island Journal, shells that have been washed into a low oxygen area will turn black due to the presence of iron sulfide. Click the link to see photos of an impressive collection of shells that were washed up on the beach after Hurricane Irene, many of which are black in color. Scroll down the page to read the comment about black seashells.
Jingle shells can be orange, yellow, white or off white, and gray. Because of the coloring and their flat shiny surface they are sometimes called “Mermaid’s toenails”. Once you hold a jingle shell, the difference between it and other shells is readily apparent. It’s a bivalve, but there is nothing to suggest it was attached to anther piece. The shell is irregular and somewhat flattened. They are rarely over 2 inches across in size.
In fact I did collect quite a few black shells that day. I’m not really sure what that black one is in the photo below. It was too thick to be a jingle shell, but had the right shape.
This piece of a whelk and the pointed bit of shell caught my eye also because of the unusual dark color. I have decided it is a Lightning Whelk. It is my best guess as the other side looks like the opening would be on the left.
I don’t think it’s rare to find a black seashell, but the shell was washed up from a place that had the right conditions to turn it into this, from it’s natural beautiful state.
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Thanks Cas, I think you are correct. We do have lots of oyster shells around here and the bumps have probably worn off. Thank you for the help!
That really dark one you couldnt identify looks like the top part of an oyster shell!!! I have one that looks just like that, but white. really beautiful pieces, especially once they get that smooth beach-glass finish from tumbling in the surf 😀
From my experience, I would say no. I have collected quite a few black shells, which have remained black. But I do love your question! If you ever find out differently, please let me know.
Would a black seashell turn back to its original color if reexposed to oxygen?