How on earth, you may ask, did the shells of marine animals - from sponges to mussels - end up producing, millions of years later, this stunningly beautiful 'design'?
Our planet once had low magnesium calcite seas where now they are high in magnesium calcite.
Climates and times change - sometimes, as here, for the good.
It certainly makes for a wonderful scarf in flowing silk with subtleties of colour that would make many artists proud.