Diamond is without a doubt the most famous precious gemstone. Clear transparent, cut diamonds are sparkly. Diamonds can come with various hints of colour and even as a black diamond variety. They are the hardest substance known to mankind. The largest diamond yet found is the Cullinan (also called the Star of Africa). It was mined in South Africa in 1905, and was given to King Edward VII of England for his birthday in 1907. The diamond was then cut into several stones.
It is the birthstone for April.