This photo doesn’t do these pretty Lettered Olives (Americoliva sayana) any justice. Sadly, the shine really isn’t showing well. You might be asking, how does a mollusk that lives in the shifting sand of the shallows maintain a shine? Weirdly enough, instead of the shell protecting the soft body, the soft body of this mollusk is often wrapped around the outside of the shell, thereby preserving the shine.
While these are not good examples of this feature, the brown swirls on the shells sometimes look like writing (hence, the common name).