Valentine's phenomenon: Japan's diamond jewellery ice

Every winter, Japan's Hokkaido coast is graced by a rare natural phenomenon called "jewellery ice", where the ice sparkles just like diamonds.

The weather is never in short supply of feeling romantic with Japan's jewellery ice. It is created along the country's Hokkaido coast and forms as ice from the Tokachi River breaks apart at the river's mouth and gets washed up on the beach.

Sand and waves together polish the ice to become extremely smooth and shiny. The phenomenon occurs only on Otsu Beach in Hokkaido, during the coldest days of winter, generally between January and February.

During winter, the temperature of the Tokachi River can drop below -20°C, but it can take a long time to freeze. This gives the ice a high transparency with no impurities.

Throughout the day, the angle of the sun bathes the ice rounds in different colours; in an orange glow at first light, to a deep blue later in the day.