Old Wive's Tale WIP

Enjoy all that the oyster gives you! And if not, then stop grumbling an' let us enjoy our oysters.

— Shelly 

Historical Basis

About fortunes found in the shelling of oysters/calms (depending on the zone). 1st - you need to find an oyster or clam (if you get this from another person it's their thoughts about you) [romance - give a shell over]
Shell open and receive small fortune, medium fortune, biggest is a warning (too much fortune to lose), and nothing means everything to gain. Eat your fortune Bury your shell under the shade of a tree; both the calm give your body energy to receive your fortune / planting under a tree gives your surrounding energy.

Spread

It's spread to the other coastal towns and has its own variations, such as fat oysters meaning luck to come or big fortunes; smaller oysters can mean either a short time waiting for luck or only a little luck to come.

Variations & Mutation

Color: depending on the density of the color, one region sees that as how lucky a person will or will not be in the next ten years of their life.
Smoothness: smoothness tends to mean if the luck will fit in well with the person's life or if the luck will cause problems. 
Size: large can mean waiting a long time for luck to come, that a person will be healthy, or that their coming fortune will make big changes.

Cultural Reception

Most inland people don't understand - all their oysters come pre-shelled and so they don't tell their fortune (in fact, most people don't eat oysters as they're too small and needed in too big of a quantity.)
Other old wives like to get together once a year and have a shelling / eating / fortune contest and they make predictions about what will happen to whom using each of their variations. Then they bet on who/what/when and split the winnings at the festival next year.

In Literature

The Problem of Women is what happens when you seek to change your fortune. Jile gave Ireala a romantic oyster.  Ireala actually likes another woman, Sirnge, and tries to switch fortunes, but that's when bad things happen. Bad luck every time Ireala tries to change or says that the reading was different - finally Ireala accepts "her fate" and realizes that she is much happy with Jile and that Sirnge was not the woman for her. (Sirnge finds her love to be the ocean)

In Art

For small children, during the festival, there are empty oyster shells to paint and give family/friends as gifts.