The cost of rubies varies widely. There are options of this birthstone on the market which are affordable. However, natural, high-quality rubies can be very costly. As it is rare to find a gem-quality ruby over one carat, the price per carat skyrockets as size increases. The most expensive ruby ever sold, the Sunrise Ruby, weighed in at a whopping 25.59 carats. It sold for over $1,000,000 per carat at a price of $30 million.