Ruby
As one of the most popular traditional gemstones, rubies have been eyed by jewellery lovers and gem aficionados around the world for centuries. In fact, fine-quality rubies are among the most expensive gemstones with record prices of over $1 million per carat. The gemstone, which occurs in medium to dark red shades and can reach vivid levels of saturation, is exceptionally durable but undergoes more treatments than almost any other gemstone.