She Sells Seashells By The Seashore,

is the start of a tongue twister,

it goes like this, 

She sells seashells by the seashore.
The shells she sells are surely seashells.
So if she sells shells on the seashore,
I'm sure she sells seashore shells.

crikey I can barely write it never mind say it! but back to seashells, millennia of natural forces have robbed ancient seashells of their various pigments, but in a new study titled, 'Diversity of Fossilised Colouration Patterns on Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells from the Neogene of the Dominican Republic', published today, well 6 hours ago as I write this, researchers discovered that by putting the shells of fossilised cone snails under an ultraviolet light, they could see what the shells may have looked like millions of years ago, looking at the picture above,
 the top row: seashells in natural light, 

middle row: seashells in UV light, 

bottom row: what the seashells would have looked like in their prime, 

in the paper the authors write, 'clearly much more work needs to be done to better understand the compounds responsible for shell colouration, that said, it seems that oxidation--caused either naturally by exposure of shells to sunlight over prolonged periods of time, or artificially by soaking in bleach for several days--plays a role in causing formerly pigmented regions of fossil shells to fluoresce under UV light, though the reason is not currently understood', under the light, areas of organic matter, where the pigment was most pronounced, light up, the researchers are still trying to figure out what compound inside the shell causes it to fluoresce, but they speculate in the paper that it might have to do with oxidation, when oxygen molecules interact with other substances, all of this from some fossilised seashells.