unusual patterned shell: low value vs valuable?

[Shells85]

Thank you for taking the time to read my post.
I am wondering if this Turritella terebra is unusual/valuable because the top whorl has vertical stripes that differ from the rest of the whorls. I have not seen any pictures of Turritella terebra shells where the top whorl's pattern is different. In the pictures I see of these shells the stripes are same on all the whorls-- in a circular pattern.

Additional information:
The shell is about 6". It is glued on a mat in a frame.
I would be Most appreciative if someone could tell me if it is low value or has any significant value. I wonder if having it--or any shell-- framed decreases its value.
Thank you for your time.