What is the rarest birthstone?

The rarest birthstone is considered to be red diamond, also known as the "fancy red diamond" or "red diamond." Red diamonds are extremely rare and highly sought after for their deep, vibrant red hue. In fact, only a few red diamonds are known to exist in the world, making them one of the most valuable and precious gemstones.

Red diamonds are considered to be even rarer than pink diamonds, which are already incredibly rare themselves. The intense red color of red diamonds is caused by the presence of a specific molecular structure within the diamond's crystal lattice, which absorbs light and creates the striking red color.

Due to their rarity and unique beauty, red diamonds are highly prized by collectors and investors alike. They are often sold at auctions for astronomical prices and are considered to be one of the most exclusive and sought-after gemstones in the world.