I am not familiar, what is the seashell leaking purple a reference to?

Saladofstones said:

I am not familiar, what is the seashell leaking purple a reference to?

It's a reference to one of the few ways one could get purple coloring in the ancient Mediterranean, which is from the secretion of several species of sea snails. The process to get this non-fading purple dye led to it being rather expensive, and the Romans prized it as a luxury item, using it to color ceremonial robes (if you've seen art of Romans in purple, or heard of the saying "born in the purple" this is where this comes from). It was so prized they even made laws over it, eventually leading to it being restricted for use only by the Imperial family.

It was known as Tyrian purple, after Tyre, Lebanon. It wouldn't be until the 19th century when a synthetic purple dye, mauveine - mauve, led to purple becoming widely adopted outside of aristocratic circles, being one of the first mass-produced synthetic dyes.